ArmPlatformPkg/ArmVirtualizationPkg: Add ArmVirtualizationQemu platform

ArmPlatformPkg/ArmVirtualizationPkg: Add ArmVirtualizationQemu platform

This adds support for executing UEFI in a QEMU/mach-virt emulated environment.
The following assumptions are made about the target:
- DRAM base at 0x4000_0000, containing the device tree blob
- DRAM size at least 1 MB
- device tree uses 64-bit physical base addresses and sizes
- ARM architected timer
- Cortex-A15 CPU (if built for 32-bit)

The following information is retrieved from the device tree:
- PL011 UART base address
- GIC base addresses
- virtual timer interrupt
- PL031 RTC base address
- DRAM size, must be at least 128 MB
- virtio MMIO transports
- PSCI 0.2 availability (for reset and poweroff)

The device tree image is relocated and installed as a configuration table
so an EFI stub enabled kernel can be booted directly without the need for
a bootloader.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Casadevall <michael.casadevall@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-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@16141 6f19259b-4bc3-4df7-8a09-765794883524