net: Cleanup redundant tests on unsigned

If there is data, the unsigned skb->len is greater than 0.

rt.sigdigits is unsigned as well, so the test `>= 0' is
always true, the other part of the test catches wrapped
values.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/x25/x25_in.c

@@ -114,7 +114,7 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp
 			/*
 			 *	Copy any Call User Data.
 			 */
-			if (skb->len >= 0) {
+			if (skb->len > 0) {
 				skb_copy_from_linear_data(skb,
 					      x25->calluserdata.cuddata,
 					      skb->len);

net/x25/x25_route.c

@@ -190,7 +190,7 @@ int x25_route_ioctl(unsigned int cmd, void __user *arg)
 		goto out;
 
 	rc = -EINVAL;
-	if (rt.sigdigits < 0 || rt.sigdigits > 15)
+	if (rt.sigdigits > 15)
 		goto out;
 
 	dev = x25_dev_get(rt.device);