Revert "DynamicTablesPkg: Rename enum used for ID Mapping"

This reverts commit 1d49a75367.

Reverting this patch as Soft Feature Freeze for
edk2-stable201903 started on 22 Feb 2019.

Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Alexei Fedorov <alexei.fedorov@arm.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Alexei Fedorov <alexei.fedorov@arm.com>

DynamicTablesPkg/Library/Acpi/Arm/AcpiIortLibArm/IortGenerator.c

@@ -44,7 +44,7 @@ Requirements:
   - EArmObjSmmuV3
   - EArmObjPmcg
   - EArmObjGicItsIdentifierArray
-  - EArmObjIdMappingArray
+  - EArmObjIdMapping
   - EArmObjGicItsIdentifierArray
 */
 
@@ -116,7 +116,7 @@ GET_OBJECT_LIST (
 */
 GET_OBJECT_LIST (
   EObjNameSpaceArm,
-  EArmObjIdMappingArray,
+  EArmObjIdMapping,
   CM_ARM_ID_MAPPING
   );
 
@@ -653,7 +653,7 @@ AddIdMappingArray (
   Generator = (ACPI_IORT_GENERATOR*)This;
 
   // Get the Id Mapping Array
-  Status = GetEArmObjIdMappingArray (
+  Status = GetEArmObjIdMapping (
              CfgMgrProtocol,
              IdMappingToken,
              &IdMappings,