vfio/pci: Disable qword access to the VGA region

Seems no reason to allow qword access to the old VGA resource. Better
restrict it to dword access as before.

Suggested-by: Alex Williamson <alex@shazbot.org>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20251218081650.555015-3-kevin.tian@intel.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

Author: ktian1

drivers/vfio/pci/vfio_pci_rdwr.c

@@ -363,7 +363,7 @@ ssize_t vfio_pci_vga_rw(struct vfio_pci_core_device *vdev, char __user *buf,
 	 * to the memory enable bit in the command register.
 	 */
 	done = vfio_pci_core_do_io_rw(vdev, false, iomem, buf, off, count,
-				      0, 0, iswrite, VFIO_PCI_IO_WIDTH_8);
+				      0, 0, iswrite, VFIO_PCI_IO_WIDTH_4);
 
 	vga_put(vdev->pdev, rsrc);