Copy QemuFwCfgLibMmio.inf to QemuFwCfgMmioDxeLib.inf,
QemuFwCfgLibMmio.inf will be deleted when all platforms switching is
completed.
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4755
Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Chao Li <lichao@loongson.cn>