iavf: allow permanent MAC address to change

Allow the VF to override the "permanent" MAC address set by the host.
This allows bonding to work in the case where the administrator has set
the VF MAC.

Note that the VF must still be set to Trusted on the host if this change
is to be accepted by the PF driver.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>