WhiskeylakeOpenBoardPkg: Add USB DCI debug suport

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3081



Add gWhiskeylakeOpenBoardPkgTokenSpaceGuid.PcdDciEnable for
USB DCI debug feature, feature is enabled if PcdDciEnable is TRUE,
it allows to debug BIOS via DCI cable.

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Signed-off-by: Heng Luo <heng.luo@intel.com>
Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com>