MdePkg: Add PI 1.5 SmramMemoryReserve HOB file

This is a special GUID extension Hob to describe SMRAM memory regions

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2020
Signed-off-by: Marc W Chen <marc.w.chen@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdePkg/MdePkg.dec

@@ -749,6 +749,9 @@
   ## Include/Guid/GraphicsInfoHob.h
   gEfiGraphicsDeviceInfoHobGuid     = { 0xe5cb2ac9, 0xd35d, 0x4430, { 0x93, 0x6e, 0x1d, 0xe3, 0x32, 0x47, 0x8d, 0xe7 }}
 
+  ## Include/Guid/SmramMemoryReserve.h
+  gEfiSmmSmramMemoryGuid            = { 0x6dadf1d1, 0xd4cc, 0x4910, { 0xbb, 0x6e, 0x82, 0xb1, 0xfd, 0x80, 0xff, 0x3d }}
+
   #
   # GUID defined in PI1.6
   #