drm/exynos: fix IS_ERR() vs NULL check in probe

The of_drm_find_bridge() does not return error pointers, it returns
NULL on error.

Fixes: dd8b6803 ("exynos: drm: dsi: Attach in_bridge in MIC driver")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_mic.c

@@ -434,9 +434,9 @@ static int exynos_mic_probe(struct platform_device *pdev)
 
 	remote = of_graph_get_remote_node(dev->of_node, 1, 0);
 	mic->next_bridge = of_drm_find_bridge(remote);
-	if (IS_ERR(mic->next_bridge)) {
+	if (!mic->next_bridge) {
 		DRM_DEV_ERROR(dev, "mic: Failed to find next bridge\n");
-		ret = PTR_ERR(mic->next_bridge);
+		ret = -EPROBE_DEFER;
 		goto err;
 	}