samsung-jxelte: display, USB network and zram fixes

As the commit message says the postmarketos-base-downstream and msm-fb-refresher are added to jxelte's device package as dependencies (The display work without the msm-fb-refresher but on the wiki it's says that it will be a good idea to install it too).

In terms of the firmware, this commit install it from the kernel source as well the modules (zram only for the moment if I'm not wrong), this make the files bcmdhd_sta.bin nvram.txt useless to install them from the firmware package, while the 'mfc_fw.bin', which resolve display things, is now installed from firmware package, same repository (if someone has time and want to change this and install the binary directly from the kernel source, will be welcome).

On the jxelte's kernel package, the '0002-fix-usb-gadget-random-mac.patch' patch, make it possible to access trought ssh using ethernet over usb, and the 'disable-charging-bootmode.patch' avoid error messages on dmesg about 'sec_battery_probe'.