ice: Implement virtchnl commands for AVF support

virtchnl is a protocol/interface specification that allows the Intel
"Adaptive Virtual Function (AVF)" driver (iavf.ko) to work with more than
one physical function driver. The AVF driver sends "virtchnl commands"
(control plane only) to the PF driver over mailbox queues and the PF driver
executes these commands and returns a result to the VF, again over mailbox.

This patch adds AVF support for the ice PF driver by implementing the
following virtchnl commands:

VIRTCHNL_OP_VERSION
VIRTCHNL_OP_GET_VF_RESOURCES
VIRTCHNL_OP_RESET_VF
VIRTCHNL_OP_ADD_ETH_ADDR
VIRTCHNL_OP_DEL_ETH_ADDR
VIRTCHNL_OP_CONFIG_VSI_QUEUES
VIRTCHNL_OP_ENABLE_QUEUES
VIRTCHNL_OP_DISABLE_QUEUES
VIRTCHNL_OP_ADD_ETH_ADDR
VIRTCHNL_OP_DEL_ETH_ADDR
VIRTCHNL_OP_CONFIG_VSI_QUEUES
VIRTCHNL_OP_ENABLE_QUEUES
VIRTCHNL_OP_DISABLE_QUEUES
VIRTCHNL_OP_REQUEST_QUEUES
VIRTCHNL_OP_CONFIG_IRQ_MAP
VIRTCHNL_OP_CONFIG_RSS_KEY
VIRTCHNL_OP_CONFIG_RSS_LUT
VIRTCHNL_OP_GET_STATS
VIRTCHNL_OP_ADD_VLAN
VIRTCHNL_OP_DEL_VLAN
VIRTCHNL_OP_ENABLE_VLAN_STRIPPING
VIRTCHNL_OP_DISABLE_VLAN_STRIPPING

Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>