MdeModulePkg DxeCore: Fix potential FV overflow of 4GB boundary on a 32-bit systems.

The traversing of a Memory Mapped FV can overflow the 4GB limit on a 32bit system
during the setting up a Linked List of FFS file inside the FV.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

git-svn-id: svn://svn.code.sf.net/p/edk2/code/trunk/edk2/MdeModulePkg@16527 6f19259b-4bc3-4df7-8a09-765794883524