MdeModulePkg/PartitionDxe: Revert changes for the special MBR

MdeModulePkg/PartitionDxe: Revert changes for the special MBR

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2823

Revert "MdeModulePkg/PartitionDxe: Skip the MBR that add for CD-ROM"

Follow the spec definition, the ISO 9660 (and UDF) would be
checked before the MBR. So it is not required to skip such
MBR talbe that contian the entire block device.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Gary Lin <glin@suse.com>
Cc: Andrew Fish <afish@apple.com>
Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>
Tested-by: Gary Lin <glin@suse.com>