IntelSiliconPkg: Add flash region GUIDs

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3307



This change identifies flash regions by GUID instead of fixed values
since the flash region identifiers are now defined in IntelSiliconPkg
and different boards may want to associate a flash region identifier
with a board/platform specific value.

The flash region GUIDs are intended to provide identifier consistency
across board implementations improving portability of the code among
IntelSiliconPkg consumers.

Cc: Ray Ni <ray.ni@intel.com>
Cc: Rangasai V Chaganty <rangasai.v.chaganty@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Sai Chaganty <rangasai.v.chaganty@intel.com>
Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com>