netfilter: xt_LOG: do print MAC header on FORWARD

I am observing consistent behavior even with bridges, so let's unlock
this. xt_mac is already usable in FORWARD, too. Section 9 of
http://ebtables.sourceforge.net/br_fw_ia/br_fw_ia.html#section9 says
the MAC source address is changed, but my observation does not match
that claim -- the MAC header is retained.

Signed-off-by: Jan Engelhardt <[e-mail]>
[Patrick; code inspection seems to confirm this]
Signed-off-by: Patrick McHardy <[e-mail]>

net/ipv4/netfilter/ipt_LOG.c

···
 	}
 #endif
 
-	/* MAC logging for input path only. */
-	if (in && !out)
+	if (in != NULL)
 		dump_mac_header(m, loginfo, skb);
 
 	dump_packet(m, loginfo, skb, 0);

net/ipv6/netfilter/ip6t_LOG.c

···
 	       in ? in->name : "",
 	       out ? out->name : "");
 
-	/* MAC logging for input path only. */
-	if (in && !out)
+	if (in != NULL)
 		dump_mac_header(m, loginfo, skb);
 
 	dump_packet(m, loginfo, skb, skb_network_offset(skb), 1);