gsm48_hdr_msg_type(): SS is in the same group as MM/CC

Change-Id: I1ddadeacced9650885f454b81f3f0df531ea1e5d
diff --git a/include/osmocom/gsm/protocol/gsm_04_08.h b/include/osmocom/gsm/protocol/gsm_04_08.h
index 4fb8a7f..c785d9f 100644
--- a/include/osmocom/gsm/protocol/gsm_04_08.h
+++ b/include/osmocom/gsm/protocol/gsm_04_08.h
@@ -1017,8 +1017,8 @@
 	switch (gsm48_hdr_pdisc(hdr)) {
 	case GSM48_PDISC_MM:
 	case GSM48_PDISC_CC:
-		return hdr->msg_type & 0x3f;
 	case GSM48_PDISC_NC_SS:
+		return hdr->msg_type & 0x3f;
 	case GSM48_PDISC_GROUP_CC:
 	case GSM48_PDISC_BCAST_CC:
 	case GSM48_PDISC_LOC: