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>

IntelFsp2WrapperPkg/IntelFsp2WrapperPkg.ci.yaml

@@ -78,11 +78,7 @@
 
     ## options defined .pytool/Plugin/LibraryClassCheck
     "LibraryClassCheck": {
-        "IgnoreLibraryClass": [
-          # This header file contains a small function in a separate library so platforms
-          # do not have to override the whole main library instance.
-          "FspWrapperPlatformMultiPhaseLib"
-        ]
+        "IgnoreLibraryClass": []
     },
 
     ## options defined .pytool/Plugin/SpellCheck