drm: exynos: dsi: Use child panel or bridge find helpers

commit <711c7adc> ("drm: exynos: dsi: Use drm panel_bridge API")
added devm_drm_of_get_bridge for looking up if child node has panel
or bridge.

However commit <b089c0a9> ("Revert "drm: of: Lookup if child node
has panel or bridge") has reverted panel or bridge child node lookup
from devm_drm_of_get_bridge which eventually failed to find the DSI
devices in exynos drm dsi driver.

So, use the conventional child panel bridge lookup helpers like it
does before.
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220428094808.782938-1-jagan@amarulasolutions.com

drivers/gpu/drm/exynos/exynos_drm_dsi.c

@@ -25,6 +25,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_mipi_dsi.h>
+#include <drm/drm_panel.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_simple_kms_helper.h>
@@ -1451,9 +1452,18 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 	struct device *dev = dsi->dev;
 	struct drm_encoder *encoder = &dsi->encoder;
 	struct drm_device *drm = encoder->dev;
+	struct drm_panel *panel;
 	int ret;
 
-	dsi->out_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
+	panel = of_drm_find_panel(device->dev.of_node);
+	if (!IS_ERR(panel)) {
+		dsi->out_bridge = devm_drm_panel_bridge_add(dev, panel);
+	} else {
+		dsi->out_bridge = of_drm_find_bridge(device->dev.of_node);
+		if (!dsi->out_bridge)
+			dsi->out_bridge = ERR_PTR(-EINVAL);
+	}
+
 	if (IS_ERR(dsi->out_bridge)) {
 		ret = PTR_ERR(dsi->out_bridge);
 		DRM_DEV_ERROR(dev, "failed to find the bridge: %d\n", ret);