gsm0480: Factor out msgb allocation helper function

Change-Id: If25b467481023eadaaf3f78157eceff4b81d24d2
diff --git a/src/gsm/gsm0480.c b/src/gsm/gsm0480.c
index 165b309..ac0fa12 100644
--- a/src/gsm/gsm0480.c
+++ b/src/gsm/gsm0480.c
@@ -787,13 +787,18 @@
 	return rc;
 }
 
+struct msgb *gsm0480_msgb_alloc_name(const char *name)
+{
+	return msgb_alloc_headroom(1024, 128, name);
+}
+
 struct msgb *gsm0480_create_ussd_resp(uint8_t invoke_id, uint8_t trans_id, const char *text)
 {
 	struct msgb *msg;
 	uint8_t *ptr8;
 	int response_len;
 
-	msg = msgb_alloc_headroom(1024, 128, "GSM 04.80");
+	msg = gsm0480_msgb_alloc_name("TS 04.80 USSD Resp");
 	if (!msg)
 		return NULL;