ramips: Use generic board detect for GnuBee devices

This is a port of an old commit from mkresin's tree:

09260cdf3e9332978c2a474a58e93a6f2b55f4a8

This has the potential to break sysupgrade but it should be fine as
there is no stable release of LEDE or OpenWrt that support these devices.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

target/linux/ramips/base-files/lib/ramips.sh

@@ -205,9 +205,6 @@ ramips_board_detect() {
 	*"FreeStation5")
 		name="freestation5"
 		;;
-	*"GB-PC1")
-		name="gb-pc1"
-		;;
 	*"GL-MT300A")
 		name="gl-mt300a"
 		;;