drm: atmel-hlcdc: actually disable scaling when no scaling is required

[ Upstream commit 1b7e38b9 ]

The driver is only enabling scaling, but never disabling it, thus, if you
enable the scaling feature once it stays enabled forever.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reported-by: Alex Vazquez <avazquez.dev@gmail.com>
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Fixes: 1a396789 ("drm: add Atmel HLCDC Display Controller support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_plane.c

@@ -335,6 +335,8 @@ atmel_hlcdc_plane_update_pos_and_size(struct atmel_hlcdc_plane *plane,
 
 		atmel_hlcdc_layer_update_cfg(&plane->layer, 13, 0xffffffff,
 					     factor_reg);
+	} else {
+		atmel_hlcdc_layer_update_cfg(&plane->layer, 13, 0xffffffff, 0);
 	}
 }