WhiskeylakeOpenBoardPkg: Correct Platform Hook Library references

Many file descriptions reference "Platform Hook Library" when the
file is not related to the PlatformHookLib library class. This
change updates those references in WhiskeylakeOpenBoardPkg to a
more accurate description.

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