vop: sparse warning fixup

vop_dc_to_vdev dropped an __iomem tag on its argument,
causing a sparse warning. Fix it up.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://lore.kernel.org/r/20200710113447.427927-1-mst@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mic/vop/vop_main.c

@@ -546,7 +546,7 @@ static int vop_match_desc(struct device *dev, void *data)
 	return vdev->desc == (void __iomem *)data;
 }
 
-static struct _vop_vdev *vop_dc_to_vdev(struct mic_device_ctrl *dc)
+static struct _vop_vdev *vop_dc_to_vdev(struct mic_device_ctrl __iomem *dc)
 {
 	return (struct _vop_vdev *)(unsigned long)readq(&dc->vdev);
 }