Apaga essa sua sources.list e cola isso nela

deb http://ftp.br.debian.org/debian/ jessie main contrib non-free
deb-src http://ftp.br.debian.org/debian/ jessie main contrib non-free

deb http://security.debian.org/ jessie/updates main contrib non-free
deb-src http://security.debian.org/ jessie/updates main contrib non-free

deb http://ftp.br.debian.org/debian/ jessie-updates main contrib non-free
deb-src http://ftp.br.debian.org/debian/ jessie-updates main contrib non-free

Depois no terminal de os comandos

su

apt update

apt install firmware-brcm80211