drm/omap: convert dss_mgr_disconnect to accept omap_channel

We are removing uses of 'struct omap_overlay_manager'. This patch
changes dss_mgr_disconnect() to accept 'enum omap_channel' instead of
'struct omap_overlay_manager'.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/dss/venc.c

@@ -761,7 +761,7 @@ static int venc_connect(struct omap_dss_device *dssdev,
 	if (r) {
 		DSSERR("failed to connect output to new device: %s\n",
 				dst->name);
-		dss_mgr_disconnect(mgr, dssdev);
+		dss_mgr_disconnect(mgr->id, dssdev);
 		return r;
 	}
 
@@ -779,7 +779,7 @@ static void venc_disconnect(struct omap_dss_device *dssdev,
 	omapdss_output_unset_device(dssdev);
 
 	if (dssdev->manager)
-		dss_mgr_disconnect(dssdev->manager, dssdev);
+		dss_mgr_disconnect(dssdev->manager->id, dssdev);
 }
 
 static const struct omapdss_atv_ops venc_ops = {