ArmVirtPkg/PciHostBridgeDxe: don't set linux,pci-probe-only DT property
    
    Setting the linux,pci-probe-only was intended to align OSes booting via
    DT with OSes booting via ACPI in the way they honor the PCI configuration
    performed by the firmware. However, ACPI on arm64 does not currently honor
    the firmware's PCI configuration, and the linux,pci-probe-only completely
    prevents any PCI reconfiguration from occurring under the OS, including
    what is needed to support PCI hotplug.
    
    Since the primary use case was OS access to the GOP framebuffer (which
    breaks when the framebuffer BAR is moved when the OS reconfigures the
    PCI), we can undo this change now that ArmVirtQemu has moved to a GOP
    implementation that does not expose a raw framebuffer in the first place.
    
    This effectively reverts commit 8b816c624dd4 ("ArmVirtPkg/VirtFdtDxe: set
    /chosen/linux,pci-probe-only to 1 in DTB")
    
    Contributed-under: TianoCore Contribution Agreement 1.0
    Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Reviewed-by: Laszlo Ersek <lersek@redhat.com>
    Ref: https://tianocore.acgmultimedia.com/show_bug.cgi?id=65