virtchnl: Add support for new VLAN capabilities

Currently VIRTCHNL only allows for VLAN filtering and offloads to happen
on a single 802.1Q VLAN. Add support to filter and offload on inner,
outer, and/or inner + outer VLANs.

This is done by introducing the new capability
VIRTCHNL_VF_OFFLOAD_VLAN_V2. The flow to negotiate this new capability
is shown below.

1. VF - sets the VIRTCHNL_VF_OFFLOAD_VLAN_V2 bit in the
   virtchnl_vf_resource.vf_caps_flags during the
   VIRTCHNL_OP_GET_VF_RESOURCES request message. The VF should also set
   the VIRTCHNL_VF_OFFLOAD_VLAN bit in case the PF driver doesn't support
   the new capability.

2. PF - sets the VLAN capability bit it supports in the
   VIRTCHNL_OP_GET_VF_RESOURCES response message. This will either be
   VIRTCHNL_VF_OFFLOAD_VLAN_V2, VIRTCHNL_VF_OFFLOAD_VLAN, or none.

3. VF - If the VIRTCHNL_VF_OFFLOAD_VLAN_V2 capability was ACK'd by the
   PF, then the VF needs to request the VLAN capabilities of the
   PF/Device by issuing a VIRTCHNL_OP_GET_OFFLOAD_VLAN...