make speech calls with NECI=1 work

Fix minor bug with speech calls in case of NECI=1
diff --git a/openbsc/src/chan_alloc.c b/openbsc/src/chan_alloc.c
index 6bf65f3..2f0d7b9 100644
--- a/openbsc/src/chan_alloc.c
+++ b/openbsc/src/chan_alloc.c
@@ -204,8 +204,10 @@
 	case GSM_LCHAN_TCH_H:
 		lchan =_lc_find_bts(bts, GSM_PCHAN_TCH_H);
 		/* If we don't have TCH/H available, fall-back to TCH/F */
-		if (!lchan)
+		if (!lchan) {
 			lchan = _lc_find_bts(bts, GSM_PCHAN_TCH_F);
+			type = GSM_LCHAN_TCH_F;
+		}
 		break;
 	default:
 		fprintf(stderr, "Unknown gsm_chan_t %u\n", type);