MdeModulePkg/UsbAbsPointer:Fix GetState() to return absolute value

MdeModulePkg/UsbAbsPointer:Fix GetState() to return absolute value

Fix UsbMouseAbsolutePointer driver GetState() interface to return
absolute value instead of relative value.
The driver is ported from UsbMouse driver. The GetState of
SimplePointer protocol returns relative value but the GetState
of AbsolutePointer protocol should return absolute value.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>