MdePkg Protocol/DevicePath.h: Update SATA Device Path comments

MdePkg Protocol/DevicePath.h: Update SATA Device Path comments

The UEFI2.5 spec (Mantis ticket 1353 -
https://mantis.uefi.org/mantis/view.php?id=1353) updated the Port
Multiplier Port Number description of SATA device path to use 0xFFFF when
the device is directly connected to the HBA.

Please note that this is an incompatible semantic change. The consumer of
SATA device path needs to re-examine its usage to follow UEFI 2.5 mantis
1353.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>