drm: get drm_bridge_panel connector via helper

The drm_connector created by drm_panel_bridge was accessed
via drm_panel.connector.
Avoid the detour around drm_panel by providing a simple get method.
This avoids direct access to the connector field in drm_panel in
the two users.

The change is done in preparation for removal of drm_panel.connector.

Update pl111 and tve200 to use the new helper.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
Cc: Jonas Karlman <jonas@kwiboo.se>
Cc: Jernej Skrabec <jernej.skrabec@siol.net>
Cc: Eric Anholt <eric@anholt.net>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191207140353.23967-5-sam@ravnborg.org

drivers/gpu/drm/tve200/tve200_drv.c

@@ -110,7 +110,7 @@ static int tve200_modeset_init(struct drm_device *dev)
 	}
 
 	priv->panel = panel;
-	priv->connector = panel->connector;
+	priv->connector = drm_panel_bridge_connector(bridge);
 	priv->bridge = bridge;
 
 	dev_info(dev->dev, "attached to panel %s\n",