octeon_ep: include function id in mailbox commands

Extend control command structure to include vfid and
update APIs to accept VF ID.

Signed-off-by: Abhijit Ayarekar <aayarekar@marvell.com>
Signed-off-by: Veerasenareddy Burru <vburru@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>