drm/panel: add rotation support for Elida KD35T133 panels

Update the panel to allow setting the rotation value in device tree.
Tested on an Odroid Go Advance, where the panel is by default rotated 270
degrees.
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/SN6PR06MB534253E1CFDEA6917230F57BA57A9@SN6PR06MB5342.namprd06.prod.outlook.com

drivers/gpu/drm/panel/panel-elida-kd35t133.c

@@ -42,6 +42,7 @@ struct kd35t133 {
 	struct gpio_desc *reset_gpio;
 	struct regulator *vdd;
 	struct regulator *iovcc;
+	enum drm_panel_orientation orientation;
 	bool prepared;
 };
 
@@ -216,6 +217,7 @@ static int kd35t133_get_modes(struct drm_panel *panel,
 	connector->display_info.width_mm = mode->width_mm;
 	connector->display_info.height_mm = mode->height_mm;
 	drm_mode_probed_add(connector, mode);
+	drm_connector_set_panel_orientation(connector, ctx->orientation);
 
 	return 1;
 }
@@ -258,6 +260,12 @@ static int kd35t133_probe(struct mipi_dsi_device *dsi)
 		return ret;
 	}
 
+	ret = of_drm_get_panel_orientation(dev->of_node, &ctx->orientation);
+	if (ret < 0) {
+		dev_err(dev, "%pOF: failed to get orientation %d\n", dev->of_node, ret);
+		return ret;
+	}
+
 	mipi_dsi_set_drvdata(dsi, ctx);
 
 	ctx->dev = dev;