net: remove SK_ROUTE_CAPS from meta ematch

Remove it, as it indirectly exposes netdev features. It's not used in
iproute2 (2.6.38) - is anything else using its interface?

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>