[NET] NETNS: Omit namespace comparision without CONFIG_NET_NS.

Introduce an inline net_eq() to compare two namespaces.
Without CONFIG_NET_NS, since no namespace other than &init_net
exists, it is always 1.

We do not need to convert 1) inline vs inline and
2) inline vs &init_net comparisons.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

net/ipv6/raw.c

@@ -76,7 +76,7 @@ static struct sock *__raw_v6_lookup(struct net *net, struct sock *sk,
 		if (inet_sk(sk)->num == num) {
 			struct ipv6_pinfo *np = inet6_sk(sk);
 
-			if (sock_net(sk) != net)
+			if (!net_eq(sock_net(sk), net))
 				continue;
 
 			if (!ipv6_addr_any(&np->daddr) &&