ArmPlatformPkg/ArmVirtualizationPkg: Add private HobLib implementation for DXE phase

ArmPlatformPkg/ArmVirtualizationPkg: Add private HobLib implementation for DXE phase

To allow a dynamically discovered UART base address, we parse the device
tree early and store the base address in a HOB. To prevent circular
constructor dependencies from interfering with bringing up the serial port
using this dynamic base address, use our own private HobLib with no
dependencies on DebugLib either directly or indirectly through UefiLib.

Contributed-under: TianoCore Contribution Agreement 1.0
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Olivier Martin <olivier.martin@arm.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16134 6f19259b-4bc3-4df7-8a09-765794883524