sfc: move vport_id to struct efx_nic

Remove some usage of ef10-specific nic_data structs from common MCDI
 functions, in preparation for using them from a non-EF10 driver.

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