ArmPlatformPkg/ArmVirtualizationPkg: add ArmVirtualizationPlatformLib library

ArmPlatformPkg/ArmVirtualizationPkg: add ArmVirtualizationPlatformLib library

This is an implementation of ArmPlatformLib that discovers the size of system
DRAM from a device tree blob located at the address passed in
gArmTokenSpaceGuid.PcdDeviceTreeBaseAddress, which should equal the value in
gArmTokenSpaceGuid.PcdSystemMemoryBase.

As the device tree blob is passed in system DRAM, this library can only be used
if sufficient DRAM is available (>= 128 MB) and if not using shadowed NOR. The
reason for this is that it makes it easier to guarantee that such a device tree
blob at base of DRAM will not be clobbered before we get a chance to preserve it.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Casadevall <michael.casadevall@linaro.org>
Acked-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@16138 6f19259b-4bc3-4df7-8a09-765794883524