patches/openwrt: linux-firmware: add QCA9377 board and firmware files

tThis is backport for OpenWrt 19.07 as said in the commit message of the patch. There was possibility to do it like it is done in OpenWrt 19.07, I mean have in one package board and firmware file, but this is not what is is done in newer versions, so I just do copy&paste

Review this version (https://gitlab.nic.cz/turris/turris-build/-/commit/f63892d41601bcaf3fbe99b1eb2ba2fb0d2ce094), but it should be same.

I will send it to upstream once @jhoracek verifies that it works. In the meantine Blocked