intel: legacy: Partial revert of field get conversion

Refactoring of the field get conversion introduced a regression in the
legacy Wake On Lan from a magic packet with i219 devices. Rx address
copied not correctly from MAC to PHY with FIELD_GET macro.

Fixes: b9a45254 ("intel: legacy: field get conversion")
Suggested-by: Vitaly Lifshits <vitaly.lifshits@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>