ArmPlatformPkg/ArmVirtualizationPkg: Add VirtFdtDxe driver

ArmPlatformPkg/ArmVirtualizationPkg: Add VirtFdtDxe driver

This driver enumerates the device nodes in the device tree located at the
base address passed in gArmTokenSpaceGuid.PcdDeviceTreeBaseAddress, and
installs drivers for devices it cares about (GIC interrupt controller, RTC,
architected timer interrupt)

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Olivier Martin <olivier.martin@arm.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16137 6f19259b-4bc3-4df7-8a09-765794883524