netfilter: ip{,6}tables_security: fix future section mismatch

Currently not visible, because NET_NS is mutually exclusive with SYSFS
which is required by SECURITY.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>