ipv6: coding style improvements (remove assignment in if statements)

This change has no functional impact and simply addresses some coding
style issues detected by checkpatch. Specifically this change
adjusts "if" statements which also include the assignment of a
variable.

No changes to the resultant object files result as determined 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 51ab096..d7d70e6 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -429,7 +429,8 @@
 		struct sk_buff *clone;
 		int i, plen = 0;
 
-		if ((clone = alloc_skb(0, GFP_ATOMIC)) == NULL)
+		clone = alloc_skb(0, GFP_ATOMIC);
+		if (clone == NULL)
 			goto out_oom;
 		clone->next = head->next;
 		head->next = clone;