[ROSE]: Fix missing unlocks in rose_route_frame()

Noticed by Coverity checker.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/rose/rose_route.c

@@ -994,8 +994,10 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25)
 	 *	1. The frame isn't for us,
 	 *	2. It isn't "owned" by any existing route.
 	 */
-	if (frametype != ROSE_CALL_REQUEST)	/* XXX */
-		return 0;
+	if (frametype != ROSE_CALL_REQUEST) {	/* XXX */
+		ret = 0;
+		goto out;
+	}
 
 	len  = (((skb->data[3] >> 4) & 0x0F) + 1) / 2;
 	len += (((skb->data[3] >> 0) & 0x0F) + 1) / 2;