ArmVirtPkg/BaseCachingPciExpressLib: depend on PciPcdProducerLib

ArmVirtPkg/BaseCachingPciExpressLib: depend on PciPcdProducerLib

Make BaseCachingPciExpressLib depend on PciPcdProducerLib, so that we
have a chance to populate PcdPciExpressBaseAddress based on the contents
of the device tree.

Also update the platforms under ArmVirtPkg that support PCI to use the
special MAX_UINT64 value as the build time default for
PcdPciExpressBaseAddress.

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