Depending on external PHY type, register access method should be
different. Clause22 or Clause45 can be chosen for different PHYs.
Implemented functions apply correct access method for used device.

Change-ID: If39d5f0da9c0b905a8cbdc1ab89885535e7d0426
Signed-off-by: Michal Kosiarz <michal.kosiarz@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>