netlink: implement nla_put_in_addr and nla_put_in6_addr

IP addresses are often stored in netlink attributes. Add generic functions
to do that.

For nla_put_in_addr, it would be nicer to pass struct in_addr but this is
not used universally throughout the kernel, in way too many places __be32 is
used to store IPv4 address.

Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 975ee5e..66cd859 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1541,11 +1541,11 @@
 		valid = INFINITY_LIFE_TIME;
 	}
 	if ((ifa->ifa_address &&
-	     nla_put_be32(skb, IFA_ADDRESS, ifa->ifa_address)) ||
+	     nla_put_in_addr(skb, IFA_ADDRESS, ifa->ifa_address)) ||
 	    (ifa->ifa_local &&
-	     nla_put_be32(skb, IFA_LOCAL, ifa->ifa_local)) ||
+	     nla_put_in_addr(skb, IFA_LOCAL, ifa->ifa_local)) ||
 	    (ifa->ifa_broadcast &&
-	     nla_put_be32(skb, IFA_BROADCAST, ifa->ifa_broadcast)) ||
+	     nla_put_in_addr(skb, IFA_BROADCAST, ifa->ifa_broadcast)) ||
 	    (ifa->ifa_label[0] &&
 	     nla_put_string(skb, IFA_LABEL, ifa->ifa_label)) ||
 	    nla_put_u32(skb, IFA_FLAGS, ifa->ifa_flags) ||