ice: Add support for VLANs and offloads

This patch adds support for VLANs. When a VLAN is created a switch filter
is added to direct the VLAN traffic to the corresponding VSI. When a VLAN
is deleted, the filter is deleted as well.

This patch also adds support for the following hardware offloads.
    1) VLAN tag insertion/stripping
    2) Receive Side Scaling (RSS)
    3) Tx checksum and TCP segmentation
    4) Rx checksum

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>