i40e: Look up MAC address in Open Firmware or IDPROM

i40e: Look up MAC address in Open Firmware or IDPROM

This is the i40e equivalent of commit c762dff24c06 ("ixgbe: Look up MAC
address in Open Firmware or IDPROM").

As with that fix, attempt to look up the MAC address in Open Firmware
on systems that support it, and use IDPROM on SPARC if no OF address
is found.

In the case of the i40e there is an assumption that the default mac
address has already been set up as the primary mac filter on probe,
so if this filter is obtained from the Open Firmware or IDPROM, an
explicit write is needed via i40e_aq_mac_address_write() and
i40e_aq_add_macvlan() invocation.

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
(cherry picked from commit c7a3fd4e5d009b6b5bc90ee373aac232a7089068)
Signed-off-by: Dhaval Giani <dhaval.giani@oracle.com>