find5: wifi: Pull CFG from stock, don't put firmware in flash file

Stock symlinks WLAN firmware from /persist

TODO:  Implement copying on boot - probably a custom variant of
init.qcom.wifi.sh will do the trick

For now, firmware and CFG must be manually copied from /persist
to /data/misc/wifi/prima/
Change-Id: I6766c8233b54abe7a60088ccae44cdb6706e5e13