[ Upstream commit 786c2077 ]

The attribute size wasn't accounted for in the get_slave_size() callback
(br_port_get_slave_size) when it was introduced, so fix it now. Also add
a policy entry for it in br_port_policy.
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: 842a9ae0 ("bridge: Extend Proxy ARP design to allow optional rules for Wi-Fi")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>