ice: Add support for VIRTCHNL_VF_OFFLOAD_VLAN_V2

ice: Add support for VIRTCHNL_VF_OFFLOAD_VLAN_V2

Add support for the VF driver to be able to request
VIRTCHNL_VF_OFFLOAD_VLAN_V2, negotiate its VLAN capabilities via
VIRTCHNL_OP_GET_OFFLOAD_VLAN_V2_CAPS, add/delete VLAN filters, and
enable/disable VLAN offloads.

VFs supporting VIRTCHNL_OFFLOAD_VLAN_V2 will be able to use the
following virtchnl opcodes:

VIRTCHNL_OP_GET_OFFLOAD_VLAN_V2_CAPS
VIRTCHNL_OP_ADD_VLAN_V2
VIRTCHNL_OP_DEL_VLAN_V2
VIRTCHNL_OP_ENABLE_VLAN_STRIPPING_V2
VIRTCHNL_OP_DISABLE_VLAN_STRIPPING_V2
VIRTCHNL_OP_ENABLE_VLAN_INSERTION_V2
VIRTCHNL_OP_DISABLE_VLAN_INSERTION_V2

Legacy VF drivers may expect the initial VLAN stripping settings to be
configured by the PF, so the PF initializes VLAN stripping based on the
VIRTCHNL_OP_GET_VF_RESOURCES opcode. However, with VLAN support via
VIRTCHNL_VF_OFFLOAD_VLAN_V2, this function is only expected to be used
for VFs that only support VIRTCHNL_VF_OFFLOAD_VLAN, which will only
be supported when a port VLAN is configured. Update the function
based on the new expectations. Also, change the message when the PF
can't enable/disable VLAN stripping to a dev_dbg() as this isn't fatal.

When a VF isn't in a port VLAN and it only supports
VIRTCHNL_VF_OFFLOAD_VLAN when Double VLAN Mode (DVM) is enabled, then
the PF needs to reject the VIRTCHNL_VF_OFFLOAD_VLAN capability and
configure the VF in software only VLAN mode. To do this add the new
function ice_vf_vsi_cfg_legacy_vlan_mode(), which updates the VF's
inner and outer ice_vsi_vlan_ops functions and sets up software only
VLAN mode.

Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>