MdeModulePkg RamDiskDxe: Report ACPI NFIT for reserved memory RAM disks

MdeModulePkg RamDiskDxe: Report ACPI NFIT for reserved memory RAM disks

The RamDiskDxe now will report RAM disks with reserved memory type to NFIT
in the ACPI table.

This commit will also make sure that an NVDIMM root device exists in the
\SB scope before reporting any RAM disk to NFIT.

To properly report the NVDIMM root device, one will need to append the
following content in the [Rule.Common.DXE_DRIVER] field in platform FDF
files:

RAW ACPI  Optional                |.acpi
RAW ASL   Optional                |.aml

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Reviewed-by: Samer El-Haj-Mahmoud <elhaj@hpe.com>