drm/sun4i: tv: Remove useless function

The drm_connector_to_sun4i_tv() function isn't used anywhere in the driver,
so let's remove it.
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220728-rpi-analog-tv-properties-v2-37-459522d653a7@cerno.tech

drivers/gpu/drm/sun4i/sun4i_tv.c

@@ -275,13 +275,6 @@ drm_encoder_to_sun4i_tv(struct drm_encoder *encoder)
 			    encoder);
 }
 
-static inline struct sun4i_tv *
-drm_connector_to_sun4i_tv(struct drm_connector *connector)
-{
-	return container_of(connector, struct sun4i_tv,
-			    connector);
-}
-
 /*
  * FIXME: If only the drm_display_mode private field was usable, this
  * could go away...