[media] davinci: vpbe: fix build error when CONFIG_VIDEO_ADV_DEBUG is enabled

Fix build error when CONFIG_VIDEO_ADV_DEBUG is enabled,
declare the vpbe_dev variable.
Signed-off-by: NLad, Prabhakar <prabhakar.lad@ti.com>
Signed-off-by: NManjunath Hadli <manjunath.hadli@ti.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/davinci/vpbe_display.c

@@ -1517,6 +1517,8 @@ static int vpbe_display_g_register(struct file *file, void *priv,
 			struct v4l2_dbg_register *reg)
 {
 	struct v4l2_dbg_match *match = &reg->match;
+	struct vpbe_fh *fh = file->private_data;
+	struct vpbe_device *vpbe_dev = fh->disp_dev->vpbe_dev;
 
 	if (match->type >= 2) {
 		v4l2_subdev_call(vpbe_dev->venc,