IntelSiliconPkg-Vtd: A new PMR interface

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1770



1) IOMMU PMR feature should be generic to support different hardware
architecture. Platforms may request no overlap between PMR regions
and system reserve memory. Create an interface to publish PLMR/PHMR
regions. It allows silicon code to adjust PLMR/PHMR region base on
the project needs.

2) A new GetVtdPmrAlignmentLib for silicon code to get
PMR alignment values.

Signed-off-by: Evelyn Wang <iwen.evelyn.wang@intel.com>
Cc: Jenny Huang <jenny.huang@intel.com>
Cc: More Shih <more.shih@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Rangasai V Chaganty <rangasai.v.chaganty@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>