[media] exynos4-is: Remove WARN_ON() from __fimc_pipeline_close()

It's not a critical error to call __fimc_pipeline_close() with missing
sensor subdev entity. Replace WARN_ON() with pr_warn() and return 0
instead of -EINVAL to fix control flow in some conditions.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/platform/exynos4-is/media-dev.c

@@ -220,16 +220,16 @@ static int __fimc_pipeline_close(struct exynos_media_pipeline *ep)
 	struct fimc_pipeline *p = to_fimc_pipeline(ep);
 	struct v4l2_subdev *sd = p ? p->subdevs[IDX_SENSOR] : NULL;
 	struct fimc_md *fmd;
-	int ret = 0;
-
-	if (WARN_ON(sd == NULL))
-		return -EINVAL;
+	int ret;
 
-	if (p->subdevs[IDX_SENSOR]) {
-		ret = fimc_pipeline_s_power(p, 0);
-		fimc_md_set_camclk(sd, false);
+	if (sd == NULL) {
+		pr_warn("%s(): No sensor subdev\n", __func__);
+		return 0;
 	}
 
+	ret = fimc_pipeline_s_power(p, 0);
+	fimc_md_set_camclk(sd, false);
+
 	fmd = entity_to_fimc_mdev(&sd->entity);
 
 	/* Disable PXLASYNC clock if this pipeline includes FIMC-IS */