ArmVirtPkg: implement ArmVirtTimerFdtClientLib

This implements a library ArmVirtTimerFdtClientLib which is intended to
be incorporated into TimerDxe via NULL library class resolution. This
allows us to make TimerDxe depend on the FDT client protocol, and
discover the timer interrupts from the device tree directly rather than
relying on VirtFdtDxe to set the dynamic PCDs.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

ArmVirtPkg/Library/ArmVirtTimerFdtClientLib/ArmVirtTimerFdtClientLib.inf

@@ -0,0 +1,49 @@
+#/** @file
+#  FDT client library for ARM's TimerDxe
+#
+#  Copyright (c) 2016, Linaro Ltd. 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.
+#
+#
+#**/
+
+[Defines]
+  INF_VERSION                    = 0x00010005
+  BASE_NAME                      = ArmVirtTimerFdtClientLib
+  FILE_GUID                      = 77EA80CA-2EFB-4AB4-8567-230D968F6B37
+  MODULE_TYPE                    = BASE
+  VERSION_STRING                 = 1.0
+  LIBRARY_CLASS                  = ArmVirtTimerFdtClientLib|DXE_DRIVER
+  CONSTRUCTOR                    = ArmVirtTimerFdtClientLibConstructor
+
+[Sources]
+  ArmVirtTimerFdtClientLib.c
+
+[Packages]
+  ArmPkg/ArmPkg.dec
+  ArmVirtPkg/ArmVirtPkg.dec
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  PcdLib
+  UefiBootServicesTableLib
+
+[Protocols]
+  gFdtClientProtocolGuid                                ## CONSUMES
+
+[Pcd]
+  gArmTokenSpaceGuid.PcdArmArchTimerSecIntrNum
+  gArmTokenSpaceGuid.PcdArmArchTimerIntrNum
+  gArmTokenSpaceGuid.PcdArmArchTimerVirtIntrNum
+  gArmTokenSpaceGuid.PcdArmArchTimerHypIntrNum
+
+[Depex]
+  gFdtClientProtocolGuid