xfrm: optimize ipv4 selector matching

Current addr_match() is errh, under-optimized.

Compiler doesn't know that memcmp() branch doesn't trigger for IPv4.
Also, pass addresses by value -- they fit into register.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 552df27..593c8a1 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -61,8 +61,8 @@
 {
 	const struct flowi4 *fl4 = &fl->u.ip4;
 
-	return  addr_match(&fl4->daddr, &sel->daddr, sel->prefixlen_d) &&
-		addr_match(&fl4->saddr, &sel->saddr, sel->prefixlen_s) &&
+	return  addr4_match(fl4->daddr, sel->daddr.a4, sel->prefixlen_d) &&
+		addr4_match(fl4->saddr, sel->saddr.a4, sel->prefixlen_s) &&
 		!((xfrm_flowi_dport(fl, &fl4->uli) ^ sel->dport) & sel->dport_mask) &&
 		!((xfrm_flowi_sport(fl, &fl4->uli) ^ sel->sport) & sel->sport_mask) &&
 		(fl4->flowi4_proto == sel->proto || !sel->proto) &&