[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/decnet/af_decnet.c b/net/decnet/af_decnet.c
index aabe98d..57d5749 100644
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -474,7 +474,7 @@
 static struct sock *dn_alloc_sock(struct net *net, struct socket *sock, gfp_t gfp)
 {
 	struct dn_scp *scp;
-	struct sock *sk = sk_alloc(net, PF_DECnet, gfp, &dn_proto, 1);
+	struct sock *sk = sk_alloc(net, PF_DECnet, gfp, &dn_proto);
 
 	if  (!sk)
 		goto out;