ArmVirtPkg/ArmVirtQemu: add ArmVirtMemInfoLib implementation

Create a new ArmVirtMemInfoLib for ArmVirtQemuKernel by cloning the
existing ArmPlatformGetVirtualMemoryMap () for this platform,
(ArmQemuRelocatablePlatformLib *not* ArmVirtPlatformLib), and cleaning
it up:
- remove support for uncached DRAM mappings
- replace EFI_D_xxx with DEBUG_xxx throughout
- use a temp variable to hold the top of the physical address space
- use AllocatePool () instead of AllocatePages (), given that we use
  160 bytes only, and the memory is never freed.

In a future patch, we will add this library to the ordinary ArmVirtQemu
platform as well.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

ArmVirtPkg/Library/QemuVirtMemInfoLib/AArch64/PhysAddrTop.S

@@ -0,0 +1,39 @@
+#
+#  Copyright (c) 2011-2013, ARM Limited. All rights reserved.
+#  Copyright (c) 2016-2017, Linaro Limited. All rights reserved.
+#
+#  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
+#  http://opensource.org/licenses/bsd-license.php
+#
+#  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+#
+#
+
+#include <AsmMacroIoLibV8.h>
+
+//EFI_PHYSICAL_ADDRESS
+//GetPhysAddrTop (
+//  VOID
+//  );
+ASM_FUNC(ArmGetPhysAddrTop)
+  mrs   x0, id_aa64mmfr0_el1
+  adr   x1, .LPARanges
+  and   x0, x0, #7
+  ldrb  w1, [x1, x0]
+  mov   x0, #1
+  lsl   x0, x0, x1
+  ret
+
+//
+// Bits 0..2 of the AA64MFR0_EL1 system register encode the size of the
+// physical address space support on this CPU:
+// 0 == 32 bits, 1 == 36 bits, etc etc
+// 6 and 7 are reserved
+//
+.LPARanges:
+  .byte 32, 36, 40, 42, 44, 48, -1, -1
+
+ASM_FUNCTION_REMOVE_IF_UNREFERENCED