drm/panel: feiyang-fy07024di26a30d: use drm_panel backlight support

Use the backlight support in drm_panel to simplify the driver
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Jagan Teki <jagan@amarulasolutions.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191207140353.23967-9-sam@ravnborg.org

drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c

@@ -9,7 +9,6 @@
 #include <drm/drm_panel.h>
 #include <drm/drm_print.h>
 
-#include <linux/backlight.h>
 #include <linux/gpio/consumer.h>
 #include <linux/delay.h>
 #include <linux/module.h>
@@ -22,7 +21,6 @@ struct feiyang {
 	struct drm_panel	panel;
 	struct mipi_dsi_device	*dsi;
 
-	struct backlight_device	*backlight;
 	struct regulator	*dvdd;
 	struct regulator	*avdd;
 	struct gpio_desc	*reset;
@@ -102,7 +100,6 @@ static int feiyang_enable(struct drm_panel *panel)
 	msleep(200);
 
 	mipi_dsi_dcs_set_display_on(ctx->dsi);
-	backlight_enable(ctx->backlight);
 
 	return 0;
 }
@@ -111,7 +108,6 @@ static int feiyang_disable(struct drm_panel *panel)
 {
 	struct feiyang *ctx = panel_to_feiyang(panel);
 
-	backlight_disable(ctx->backlight);
 	return mipi_dsi_dcs_set_display_off(ctx->dsi);
 }
 
@@ -225,9 +221,9 @@ static int feiyang_dsi_probe(struct mipi_dsi_device *dsi)
 		return PTR_ERR(ctx->reset);
 	}
 
-	ctx->backlight = devm_of_find_backlight(&dsi->dev);
-	if (IS_ERR(ctx->backlight))
-		return PTR_ERR(ctx->backlight);
+	ret = drm_panel_of_backlight(&ctx->panel);
+	if (ret)
+		return ret;
 
 	ret = drm_panel_add(&ctx->panel);
 	if (ret < 0)