IntelFsp2WrapperPkg: Remove CI exception of PlatformMultiPhaseLib.

IntelFsp2WrapperPkg: Remove CI exception of PlatformMultiPhaseLib.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4092

Duplicate library class header issue will be resolved and CI
exception for FspWrapperPlatformMultiPhaseLib should be removed too.

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