Add legacy suffix to mailbox functions which should be backwards compatible
with older PF drivers. Communication during API negotiation always has to
be done using the earlier implementation.
Signed-off-by: Radoslaw Tyl <radoslawx.tyl@intel.com>
Tested-by: Tony Brelinski <tony.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>