fairphone-fp4: kernel upgrade & package nonfree firmware

Now supporting sd card, modem (kinda), wifi, display backlight, other misc remoteprocs (adsp & cdsp) and in theory maybe mobile data.

With this you can get the modem and wifi running nearly out of the box. As the kernel currently doesn't support UFS (internal storage) you need to dump the following partitions using dd in TWRP or similar:

fsc, fsg, modemst1, modemst2, tunning

Place those as files in the rootfs in /modem-partitions/ and add "-o /modem-partitions" to the rmtfs arguments by modifying /etc/init.d/rmtfs and changing command_args to "-P -r -o /modem-partitions".

Also worth noting that I haven't managed to actually managed to get mobile network up fully, more details at https://gitlab.freedesktop.org/mobile-broadband/ModemManager/-/issues/484 And because of that mobile data is not validated yet either.