qemu: ramfb video device doesn't support PCI address

qemu: ramfb video device doesn't support PCI address

Although a ramfb video device is not a PCI device, we don't currently
report an error for ramfb device definitions containing a PCI address.
However, a guest configured with such a device will fail to start:

    # virsh start test1
    error: Failed to start domain test1
    error: internal error: qemu unexpectedly closed the monitor: 2020-06-16T05:23:02.759221Z qemu-kvm: -device ramfb,id=video0,bus=pcie.0,addr=0x1: Device 'ramfb' can't go on PCIE bus

A better approach is to reject any device definitions that contain PCI
addresses.  While this is a change in behavior, any existing
configurations were non-functional.

https://bugzilla.redhat.com/show_bug.cgi?id=1847259

Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>