drm/rcar-du: Fix buffer pitch alignment

The DU requires a 16 pixels pitch alignement. Make sure dumb buffers are
allocated with the correct pitch, and validate the pitch when creating
frame buffers.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.c b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
index 003b34e..ff82877 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
@@ -251,7 +251,7 @@
 	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
 	.gem_prime_import	= drm_gem_cma_dmabuf_import,
 	.gem_prime_export	= drm_gem_cma_dmabuf_export,
-	.dumb_create		= drm_gem_cma_dumb_create,
+	.dumb_create		= rcar_du_dumb_create,
 	.dumb_map_offset	= drm_gem_cma_dumb_map_offset,
 	.dumb_destroy		= drm_gem_cma_dumb_destroy,
 	.fops			= &rcar_du_fops,