compiler warnings

/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/core/rtw_ap.c: In function 'rtw_add_bcn_ie':
/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/core/rtw_ap.c:228:24: warning: 'ielen' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if (p != NULL && ielen>0)
                   ~~~~~^~
[...]
  Building modules, stage 2.
  MODPOST 1 modules
WARNING: "wiphy_free" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_unlink_bss" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_connect_done" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "ieee80211_frequency_to_channel" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_rx_mgmt" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_mgmt_tx_status" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_vendor_cmd_reply" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_get_bss" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "wiphy_unregister" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_del_sta_sinfo" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "ieee80211_get_channel" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_michael_mic_failure" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "wiphy_apply_custom_regulatory" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_ibss_joined" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "__cfg80211_send_event_skb" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_roamed" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_put_bss" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "__cfg80211_alloc_event_skb" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "__cfg80211_alloc_reply_skb" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "wiphy_register" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_ready_on_channel" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "wiphy_new_nm" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_disconnected" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_new_sta" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_remain_on_channel_expired" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_scan_done" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!
WARNING: "cfg80211_inform_bss_frame_data" [/home/[...]/opt/2/openwrt/build_dir/target-arm_cortex-a7+neon-vfpv4_musl_eabi/linux-sunxi_cortexa7/rtl8189ES_linux/8189fs.ko] undefined!