[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/ipx/af_ipx.c b/net/ipx/af_ipx.c
index 29b063d..a195a66 100644
--- a/net/ipx/af_ipx.c
+++ b/net/ipx/af_ipx.c
@@ -1381,7 +1381,7 @@
 		goto out;
 
 	rc = -ENOMEM;
-	sk = sk_alloc(net, PF_IPX, GFP_KERNEL, &ipx_proto, 1);
+	sk = sk_alloc(net, PF_IPX, GFP_KERNEL, &ipx_proto);
 	if (!sk)
 		goto out;
 #ifdef IPX_REFCNT_DEBUG