gbproxy: Fix confusing log message in gbprox_relay2nse

This function is now used to transmit messages in both directions,
BSS->SGSN and SGSN->BSS.
Print the actual direction in the logs

Change-Id: I31682156dfe88f7ca121a711968e625caed8bd5e
Related: OS#4472
diff --git a/src/gbproxy/gb_proxy.c b/src/gbproxy/gb_proxy.c
index d84da1a..ca1c07c 100644
--- a/src/gbproxy/gb_proxy.c
+++ b/src/gbproxy/gb_proxy.c
@@ -148,8 +148,8 @@
 	uint32_t tlli;
 	int rc;
 
-	DEBUGP(DGPRS, "NSE(%05u/SGSN)-BVC(%05u) proxying SGSN->BSS NSE(%05u/BSS)\n",
-		msgb_nsei(msg), ns_bvci, nse->nsei);
+	DEBUGP(DGPRS, "NSE(%05u/%s)-BVC(%05u/??) proxying to NSE(%05u/%s)\n", msgb_nsei(msg),
+	       !nse->sgsn_facing ? "SGSN" : "BSS", ns_bvci, nse->nsei, nse->sgsn_facing ? "SGSN" : "BSS");
 
 	nsp.bvci = ns_bvci;
 	nsp.nsei = nse->nsei;