MdePkg: Fix ACPI memory aggregator/device type mismatch

MdePkg: Fix ACPI memory aggregator/device type mismatch

Bugzilla: 3578 (https://bugzilla.tianocore.org/show_bug.cgi?id=3579)

Since the Common Memory Device (formerly Memory Aggregator Device) was
introduced in ACPI 5.0, the edk2 type values have not matched the
values defined in the ACPI specification.

Fix this discrepancy by aligning the code to match the specification.

Signed-off-by: Chris Jones <christopher.jones@arm.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>