libmsc/sgs_iface.c: fix SGS_STATE_NS11 counter reference

The SGS_STATE_TS11 is not for counters, it's for timers!

Change-Id: Ifbb1a37e644ae8bf8e7959f6f6cd6403ac1f2f1b
Fixes: CID#190872 Out-of-bounds read (OVERRUN)
diff --git a/src/libmsc/sgs_iface.c b/src/libmsc/sgs_iface.c
index 1c2146a..4f262a5 100644
--- a/src/libmsc/sgs_iface.c
+++ b/src/libmsc/sgs_iface.c
@@ -1129,7 +1129,7 @@
 			mme->ns11_remaining--;
 		} else {
 			LOGMME(mme, LOGL_ERROR, "Ts11 expired more than %u (Ns11) times, giving up\n",
-			       sgs->cfg.counter[SGS_STATE_TS11]);
+			       sgs->cfg.counter[SGS_STATE_NS11]);
 			osmo_fsm_inst_state_chg(fi, SGS_VLRR_ST_NULL, 0, 0);
 		}
 		break;