OvmfPkg: AcpiPlatformDxe: enable PCI IO and MMIO while fetching QEMU tables
    
    Now that the previous patches ensure that we can access all PCI devices in
    AcpiPlatformDxe, we can enable IO and MMIO decoding for all of them while
    we contact QEMU for the ACPI tables. See more details in the patch titled:
    
      OvmfPkg: introduce gRootBusesConnectedProtocolGuid
    
    In particular, this patch will prevent the bug when the 64-bit MMIO
    aperture is completely missing from QEMU's _CRS, and consequently Linux
    rejects 64-bit BARs with the error message
    
      pci 0000:00:03.0: can't claim BAR 4 [mem 0x800000000-0x8007fffff 64bit
                        pref]: no compatible bridge window
    
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Gerd Hoffmann <kraxel@redhat.com>
    Cc: Jordan Justen <jordan.l.justen@intel.com>
    Cc: Marcel Apfelbaum <marcel@redhat.com>
    Contributed-under: TianoCore Contribution Agreement 1.0
    Signed-off-by: Laszlo Ersek <lersek@redhat.com>