MdeModulePkg: Unregister DXE FpdtStatusCodeHandler.

DXE FpdtStatusCodeHandler is required to be unregistered even if StatusCodeReport is disabled. This change makes sure FpdtStatusCodeHandler be always unregistered.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Vincent Zimmer <vincent.zimmer@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/MdeModulePkg@16470 6f19259b-4bc3-4df7-8a09-765794883524