octeon_ep: control net framework to support VF offloads

Inquire firmware on supported offloads, as well as convey offloads
enabled dynamically to firmware for the VFs. Implement control net API
to support the same.

Signed-off-by: Shinas Rasheed <srasheed@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>