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>
diff --git a/net/x25/x25_route.c b/net/x25/x25_route.c
index 2c999cc..66961ea 100644
--- a/net/x25/x25_route.c
+++ b/net/x25/x25_route.c
@@ -190,7 +190,7 @@
 		goto out;
 
 	rc = -EINVAL;
-	if (rt.sigdigits < 0 || rt.sigdigits > 15)
+	if (rt.sigdigits > 15)
 		goto out;
 
 	dev = x25_dev_get(rt.device);