drm: omap: Rely on the default ->best_encoder() behavior

We have a 1:1 relationship between connectors and encoders and the
driver is relying on the atomic helpers: we can drop the custom
->best_encoder() implementation and let the core call
drm_atomic_helper_best_encoder() for us.

Signed-off-by: Boris Brezillon <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: http://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/omapdrm/omap_connector.c

···
 struct omap_connector {
 	struct drm_connector base;
 	struct omap_dss_device *dssdev;
-	struct drm_encoder *encoder;
 	bool hdmi_mode;
 };
 
···
 	return ret;
 }
 
-struct drm_encoder *omap_connector_attached_encoder(
-		struct drm_connector *connector)
-{
-	struct omap_connector *omap_connector = to_omap_connector(connector);
-	return omap_connector->encoder;
-}
-
 static const struct drm_connector_funcs omap_connector_funcs = {
 	.dpms = drm_atomic_helper_connector_dpms,
 	.reset = drm_atomic_helper_connector_reset,
···
 static const struct drm_connector_helper_funcs omap_connector_helper_funcs = {
 	.get_modes = omap_connector_get_modes,
 	.mode_valid = omap_connector_mode_valid,
-	.best_encoder = omap_connector_attached_encoder,
 };
 
 /* initialize connector */
···
 		goto fail;
 
 	omap_connector->dssdev = dssdev;
-	omap_connector->encoder = encoder;
 
 	connector = &omap_connector->base;