i40e: Lock for VSI's MAC filter list

This patch introduces a spinlock which is to be used for synchronizing
access to VSI's MAC filter list.

This patch also synchronizes execution of other codepaths which are
accessing VSI's MAC filter list with execution of
service_task:sync_vsi_filters.

In function i40e_add_vsi, copied out LAA MAC address instead of cloning
MAC filter entry because only MAC address is needed to remove MAC VLAN
filter from FW/HW.

Change-ID: I0e10ac7c715d44aa994239642aa4d57c998573a2
Signed-off-by: Kiran Patil <kiran.patil@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>