gbproxy: Add context info to log messages

This mainly adds the NSEI to the messages, similar to log messages
ogf the existing gbproxy code.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/gprs/gb_proxy.c b/openbsc/src/gprs/gb_proxy.c
index 549d3d7..8bad721 100644
--- a/openbsc/src/gprs/gb_proxy.c
+++ b/openbsc/src/gprs/gb_proxy.c
@@ -1982,7 +1982,9 @@
 	OSMO_ASSERT(err_ctr >= 0);
 	rate_ctr_inc(&peer->ctrg->ctr[err_ctr]);
 	LOGP(DGPRS, LOGL_ERROR,
-	     "Failed to patch BSSGP message as requested: %s.\n", err_info);
+	     "NSEI=%u(%s) failed to patch BSSGP message as requested: %s.\n",
+	     msgb_nsei(msg), parse_ctx->to_bss ? "SGSN" : "BSS",
+	     err_info);
 }
 
 /* patch BSSGP message */
@@ -2008,7 +2010,9 @@
 	if (!rc) {
 		if (!parse_ctx.need_decryption) {
 			LOGP(DGPRS, LOGL_ERROR,
-			     "Failed to parse BSSGP/GMM message\n");
+			     "NSEI=%u(BSS) patching: "
+			     "failed to parse BSSGP/GMM message\n",
+			     msgb_nsei(msg));
 			return;
 		}
 	}
@@ -2071,7 +2075,9 @@
 	if (!rc) {
 		if (!parse_ctx.need_decryption) {
 			LOGP(DGPRS, LOGL_ERROR,
-			     "Failed to parse BSSGP/GMM message\n");
+			     "NSEI=%u(SGSN) patching: "
+			     "failed to parse BSSGP/GMM message\n",
+			     msgb_nsei(msg));
 			return;
 		}
 	}