drm/vc4: plane: Use return variable in atomic_check

The vc4_plane_atomic_check() directly returns the result of the final
function it calls.

Using the already defined ret variable to check its content on error,
and a separate return 0 on success, makes it easier to extend.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240621152055.4180873-13-dave.stevenson@raspberrypi.com
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>

drivers/gpu/drm/vc4/vc4_plane.c

@@ -1386,7 +1386,11 @@ static int vc4_plane_atomic_check(struct drm_plane *plane,
 	if (ret)
 		return ret;
 
-	return vc4_plane_allocate_lbm(new_plane_state);
+	ret = vc4_plane_allocate_lbm(new_plane_state);
+	if (ret)
+		return ret;
+
+	return 0;
 }
 
 static void vc4_plane_atomic_update(struct drm_plane *plane,