netfilter: ipset: Actually allow destination MAC address for hash:ip,mac sets too

In commit 8cc4ccf5 ("ipset: Allow matching on destination MAC address
for mac and ipmac sets"), ipset.git commit 1543514c46a7, I removed the
KADT check that prevents matching on destination MAC addresses for
hash:mac sets, but forgot to remove the same check for hash:ip,mac set.

Drop this check: functionality is now commented in man pages and there's
no reason to restrict to source MAC address matching anymore.

Reported-by: Chen Yi <yiche@redhat.com>
Fixes: 8cc4ccf5 ("ipset: Allow matching on destination MAC address for mac and ipmac sets")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>