ipv6: coding style: comparison for inequality 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/ip6_output.c b/net/ipv6/ip6_output.c
index 8b6d402..84c58da 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -657,7 +657,7 @@
 				fh->nexthdr = nexthdr;
 				fh->reserved = 0;
 				fh->frag_off = htons(offset);
-				if (frag->next != NULL)
+				if (frag->next)
 					fh->frag_off |= htons(IP6_MF);
 				fh->identification = frag_id;
 				ipv6_hdr(frag)->payload_len =