[media] v4l2: add const to argument of write-only s_register ioctl

This ioctl is defined as IOW, so pass the argument as const.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/usb/pvrusb2/pvrusb2-hdw.h b/drivers/media/usb/pvrusb2/pvrusb2-hdw.h
index 8060fc6..91bae93 100644
--- a/drivers/media/usb/pvrusb2/pvrusb2-hdw.h
+++ b/drivers/media/usb/pvrusb2/pvrusb2-hdw.h
@@ -240,7 +240,7 @@
    setFl   - true to set the register, false to read it
    val_ptr - storage location for source / result. */
 int pvr2_hdw_register_access(struct pvr2_hdw *,
-			     struct v4l2_dbg_match *match, u64 reg_id,
+			     const struct v4l2_dbg_match *match, u64 reg_id,
 			     int setFl, u64 *val_ptr);
 
 /* The following entry points are all lower level things you normally don't