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>
diff --git a/drivers/gpu/drm/omapdrm/dss/output.c b/drivers/gpu/drm/omapdrm/dss/output.c
index 24de7cd..0ca46f3 100644
--- a/drivers/gpu/drm/omapdrm/dss/output.c
+++ b/drivers/gpu/drm/omapdrm/dss/output.c
@@ -195,10 +195,10 @@
 }
 EXPORT_SYMBOL(dss_mgr_connect);
 
-void dss_mgr_disconnect(struct omap_overlay_manager *mgr,
+void dss_mgr_disconnect(enum omap_channel channel,
 		struct omap_dss_device *dst)
 {
-	dss_mgr_ops->disconnect(mgr->id, dst);
+	dss_mgr_ops->disconnect(channel, dst);
 }
 EXPORT_SYMBOL(dss_mgr_disconnect);