ramfb: Add property to control if load the romfile

ramfb: Add property to control if load the romfile

Currently the ramfb device loads the vgabios-ramfb.bin unconditionally,
but only the x86 need the vgabios-ramfb.bin, this can cause that when
use the release package on arm64 it can't find the vgabios-ramfb.bin.

Because only seabios will use the vgabios-ramfb.bin, load the rom logic
is x86-specific. For other !x86 platforms, the edk2 ships an EFI driver
for ramfb, so they don't need to load the romfile.

So add a new property use-legacy-x86-rom in both ramfb and vfio_pci
device, because the vfio display also use the ramfb_setup() to load
the vgabios-ramfb.bin file.

After have this property, the machine type can set the compatibility to
not load the vgabios-ramfb.bin if the arch doesn't need it.

For now the default value is true but it will be turned off by default
in subsequent patch when compats get properly handled.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Shaoqin Huang <shahuang@redhat.com>
Message-ID: <20250717100941.2230408-2-shahuang@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>