gbproxy: Have a clear namespace for the public functions

Done with Jacob
diff --git a/openbsc/src/gprs/gb_proxy_vty.c b/openbsc/src/gprs/gb_proxy_vty.c
index ee13e4c..41129d8 100644
--- a/openbsc/src/gprs/gb_proxy_vty.c
+++ b/openbsc/src/gprs/gb_proxy_vty.c
@@ -509,7 +509,7 @@
 		break;
 	}
 
-	peer = peer_by_nsei(nsei);
+	peer = gbprox_peer_by_nsei(nsei);
 	if (!peer) {
 		vty_out(vty, "Didn't find peer with NSEI %d%s",
 			nsei, VTY_NEWLINE);