gprs_ns2: add new vty2

Change-Id: I163279cf57e84198dc8c53e1c109f5a9474670e9
diff --git a/src/gb/gprs_ns2_vty.c b/src/gb/gprs_ns2_vty.c
index e33869b..9e09f0d 100644
--- a/src/gb/gprs_ns2_vty.c
+++ b/src/gb/gprs_ns2_vty.c
@@ -935,6 +935,9 @@
 		case GPRS_NS2_LL_FR_GRE:
 			dialect = NS2_DIALECT_STATIC_RESETBLOCK;
 			continue;
+		case GPRS_NS2_LL_UNDEF:
+			/* should not happen */
+			OSMO_ASSERT(false);
 		}
 
 		nse = gprs_ns2_nse_by_nsei(vty_nsi, vtyvc->nsei);
@@ -984,6 +987,7 @@
 			break;
 		}
 		case GPRS_NS2_LL_FR_GRE:
+		case GPRS_NS2_LL_UNDEF:
 			continue;
 		}
 	}