ixgbe: add handler for devlink .info_get()

Provide devlink .info_get() callback implementation to allow the
driver to report detailed version information. The following info
is reported:

 "serial_number" -> The PCI DSN of the adapter
 "fw.bundle_id" -> Unique identifier for the combined flash image
 "fw.undi" -> Version of the Option ROM containing the UEFI driver
 "board.id" -> The PBA ID string

Reviewed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Tested-by: Bharath R <bharath.r@intel.com>
Signed-off-by: Jedrzej Jagielski <jedrzej.jagielski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>