drm: bridge: dw-hdmi: Pass private data pointer to .mode_valid()

Platform glue drivers for dw_hdmi may need to access device-specific
data from their .mode_valid() implementation. They currently have no
clean way to do so, and one driver hacks around it by accessing the
dev_private data of the drm_device retrieved from the connector.

Add a priv_data void pointer to the dw_hdmi_plat_data structure, and
pass it to the .mode_valid() function.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200526011505.31884-12-laurent.pinchart+renesas@ideasonboard.com

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c

@@ -2771,6 +2771,7 @@ dw_hdmi_bridge_mode_valid(struct drm_bridge *bridge,
 			  const struct drm_display_mode *mode)
 {
 	struct dw_hdmi *hdmi = bridge->driver_private;
+	const struct dw_hdmi_plat_data *pdata = hdmi->plat_data;
 	struct drm_connector *connector = &hdmi->connector;
 	enum drm_mode_status mode_status = MODE_OK;
 
@@ -2778,8 +2779,9 @@ dw_hdmi_bridge_mode_valid(struct drm_bridge *bridge,
 	if (mode->flags & DRM_MODE_FLAG_DBLCLK)
 		return MODE_BAD;
 
-	if (hdmi->plat_data->mode_valid)
-		mode_status = hdmi->plat_data->mode_valid(connector, mode);
+	if (pdata->mode_valid)
+		mode_status = pdata->mode_valid(hdmi, pdata->priv_data,
+						connector, mode);
 
 	return mode_status;
 }