ice: Use the proto argument for VLAN ops

Currently the proto argument is unused. This is because the driver only
supports 802.1Q VLAN filtering. This policy is enforced via netdev
features that the driver sets up when configuring the netdev, so the
proto argument won't ever be anything other than 802.1Q. However, this
will allow for future iterations of the driver to seemlessly support
802.1ad filtering. Begin using the proto argument and extend the related
structures to support its use.

Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>