ipv4: coding style: comparison for inequality with NULL

The ipv4 code uses a mixture of coding styles. In some instances check
for non-NULL pointer is done as x != NULL and sometimes as x. x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.

No changes detected by objdiff.

Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index 5b3d91b..bd24679 100644
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -264,7 +264,7 @@
 	unsigned char *iph;
 	int optlen, l;
 
-	if (skb != NULL) {
+	if (skb) {
 		rt = skb_rtable(skb);
 		optptr = (unsigned char *)&(ip_hdr(skb)[1]);
 	} else