i40e: Fix MAC format in Write MAC address AQ cmd

The MAC address format expected by the hardware is in a very specific
format, and the driver was filling in the data incorrectly.

Change-ID: I7bc66505ef459ee347dd3bda68051004c141c689
Signed-off-by: Kamil Krawczyk <kamil.krawczyk@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>