[NET]: Forget the zero_it argument of sk_alloc()

Finally, the zero_it argument can be completely removed from
the callers and from the function prototype.

Besides, fix the checkpatch.pl warnings about using the
assignments inside if-s.

This patch is rather big, and it is a part of the previous one.
I splitted it wishing to make the patches more readable. Hope 
this particular split helped.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index 1b1caf3..ecbd388 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -162,7 +162,7 @@
 	BUG_TRAP(answer_prot->slab != NULL);
 
 	err = -ENOBUFS;
-	sk = sk_alloc(net, PF_INET6, GFP_KERNEL, answer_prot, 1);
+	sk = sk_alloc(net, PF_INET6, GFP_KERNEL, answer_prot);
 	if (sk == NULL)
 		goto out;