initrd/init:set_fs_linux() (tahrpup)

# LN#705 to 711 of /intrd/init tahrpup - https://www.pearltrees.com/s243a/initrd-init/id19535893/item224274706
# Ln# 757 to 763 of https://github.com/puppylinux-woof-CE/woof-CE/blob/c96d661c2232caef1d69c693de673fb0e54796f8/initrd-progs/0initrd/init#L757 (13 Mar 2018)
set_fs_linux() {
# "$1" - file system type - ex: ext4
 ONE_FS_IS_LINUX=""
 case ${1} in
  ext2|ext3|ext4|reiserfs|minix|f2fs) ONE_FS_IS_LINUX="yes" ;;
 esac
}