sfc: make capability checking a nic_type function

Various MCDI functions (especially in filter handling) need to check the
 datapath caps, but those live in nic_data (since they don't exist on
 Siena).  Decouple from ef10-specific data structures by adding check_caps
 to the nic_type, to allow using these functions from non-ef10 drivers.

Also add a convenience macro efx_has_cap() to reduce the amount of
 boilerplate involved in calling it.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>