drm/vc4: Fix scaling of uni-planar formats

When using uni-planar formats (like RGB), the scaling parameters are
stored in plane 0, not plane 1.

Fixes: fc04023 ("drm/vc4: Add support for YUV planes.")
Cc: [email protected]
Signed-off-by: Boris Brezillon <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: Boris Brezillon

drivers/gpu/drm/vc4/vc4_plane.c

@@ -503,7 +503,7 @@ static int vc4_plane_mode_set(struct drm_plane *plane,
 	 * the scl fields here.
 	 */
 	if (num_planes == 1) {
-		scl0 = vc4_get_scl_field(state, 1);
+		scl0 = vc4_get_scl_field(state, 0);
 		scl1 = scl0;
 	} else {
 		scl0 = vc4_get_scl_field(state, 1);