drm: renesas: shmobile: Use drmm_universal_plane_alloc()

According to the comments for drm_universal_plane_init(), the plane
structure should not be allocated with devm_kzalloc().

Fix lifetime issues by using drmm_universal_plane_alloc() instead.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/65ebf0513e2836227a9636e922f51c668bd69720.1694767209.git.geert+renesas@glider.be

drivers/gpu/drm/renesas/shmobile/shmob_drm_plane.c

@@ -179,7 +179,6 @@ static int shmob_drm_plane_disable(struct drm_plane *plane,
 static const struct drm_plane_funcs shmob_drm_plane_funcs = {
 	.update_plane = shmob_drm_plane_update,
 	.disable_plane = shmob_drm_plane_disable,
-	.destroy = drm_plane_cleanup,
 };
 
 static const uint32_t formats[] = {
@@ -198,19 +197,16 @@ static const uint32_t formats[] = {
 int shmob_drm_plane_create(struct shmob_drm_device *sdev, unsigned int index)
 {
 	struct shmob_drm_plane *splane;
-	int ret;
 
-	splane = devm_kzalloc(sdev->dev, sizeof(*splane), GFP_KERNEL);
-	if (splane == NULL)
-		return -ENOMEM;
+	splane = drmm_universal_plane_alloc(sdev->ddev, struct shmob_drm_plane,
+					    plane, 1, &shmob_drm_plane_funcs,
+					    formats, ARRAY_SIZE(formats), NULL,
+					    DRM_PLANE_TYPE_OVERLAY, NULL);
+	if (IS_ERR(splane))
+		return PTR_ERR(splane);
 
 	splane->index = index;
 	splane->alpha = 255;
 
-	ret = drm_universal_plane_init(sdev->ddev, &splane->plane, 1,
-				       &shmob_drm_plane_funcs,
-				       formats, ARRAY_SIZE(formats), NULL,
-				       DRM_PLANE_TYPE_OVERLAY, NULL);
-
-	return ret;
+	return 0;
 }