IntelSiliconPkg IntelVTdPmrPei: Get high top by host address width

Get high top by host address width instead of resource HOB.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>

IntelSiliconPkg/Feature/VTd/IntelVTdPmrPei/IntelVTdPmrPei.h

@@ -1,7 +1,7 @@
 /** @file
   The definition for DMA access Library.
 
-  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2017 - 2018, Intel Corporation. All rights reserved.<BR>
   This program and the accompanying materials
   are licensed and made available under the terms and conditions of the BSD License
   which accompanies this distribution.  The full text of the license may be found at
@@ -159,16 +159,6 @@ DumpAcpiDMAR (
   IN EFI_ACPI_DMAR_HEADER  *Dmar
   );
 
-/**
-  Get the highest memory.
-
-  @return the highest memory.
-**/
-UINT64
-GetTopMemory (
-  VOID
-  );
-
 extern EFI_GUID mVTdInfoGuid;
 
 #endif