ipv6: coding style: comparison for equality with NULL

The ipv6 code uses a mixture of coding styles. In some instances check for 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/ipv6/reassembly.c b/net/ipv6/reassembly.c
index d7d70e6..24fbc0a 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -430,7 +430,7 @@
 		int i, plen = 0;
 
 		clone = alloc_skb(0, GFP_ATOMIC);
-		if (clone == NULL)
+		if (!clone)
 			goto out_oom;
 		clone->next = head->next;
 		head->next = clone;
@@ -632,7 +632,7 @@
 	table = ip6_frags_ns_ctl_table;
 	if (!net_eq(net, &init_net)) {
 		table = kmemdup(table, sizeof(ip6_frags_ns_ctl_table), GFP_KERNEL);
-		if (table == NULL)
+		if (!table)
 			goto err_alloc;
 
 		table[0].data = &net->ipv6.frags.high_thresh;
@@ -648,7 +648,7 @@
 	}
 
 	hdr = register_net_sysctl(net, "net/ipv6", table);
-	if (hdr == NULL)
+	if (!hdr)
 		goto err_reg;
 
 	net->ipv6.sysctl.frags_hdr = hdr;