octeon_ep: function id in link info and stats mailbox commands

Update control mailbox API to include function id in get stats and
link info.

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