IntelFsp2Pkg/BaseFspMultiPhaseLib: Replace duplicate GUID

IntelFsp2Pkg/BaseFspMultiPhaseLib: Replace duplicate GUID

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=4048

The FILE_GUID for this library instance file is a duplicate of
Library/SecFspSecPlatformLibNull/SecFspSecPlatformLibNull.inf.

This change replaces the duplicated GUID value with a unique GUID.

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Chasel Chiu <chasel.chiu@intel.com>
Reviewed-by: Michael D Kinney <michael.d.kinney>