mtp: Turn error messages into full sentences.

Turn the error messages into full sentences that
end with a full stop. Try to put the link set name
and the link number into these messages.
diff --git a/src/mtp_layer3.c b/src/mtp_layer3.c
index 3a59b4f..69374aa 100644
--- a/src/mtp_layer3.c
+++ b/src/mtp_layer3.c
@@ -320,9 +320,9 @@
 	case MTP_TRF_RESTR_MSG_GRP:
 		switch (cmn->h1) {
 		case MTP_RESTR_MSG_ALLWED:
-			LOGP(DINP, LOGL_INFO, "Received Restart Allowed. SST could be next: %s\n", link->name);
+			LOGP(DINP, LOGL_INFO, "Received Restart Allowed. SST could be next: %s.\n", link->name);
 			link->sccp_up = 1;
-			LOGP(DINP, LOGL_INFO, "SCCP traffic allowed. %s\n", link->name);
+			LOGP(DINP, LOGL_INFO, "SCCP traffic allowed on %s.\n", link->name);
 			return 0;
 			break;
 		}