drm/omap: convert dss_mgr_unregister_framedone_handler to accept omap_channel

We are removing uses of 'struct omap_overlay_manager'. This patch
changes dss_mgr_unregister_framedone_handler() 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 637f892..829232a 100644
--- a/drivers/gpu/drm/omapdrm/dss/output.c
+++ b/drivers/gpu/drm/omapdrm/dss/output.c
@@ -241,9 +241,9 @@
 }
 EXPORT_SYMBOL(dss_mgr_register_framedone_handler);
 
-void dss_mgr_unregister_framedone_handler(struct omap_overlay_manager *mgr,
+void dss_mgr_unregister_framedone_handler(enum omap_channel channel,
 		void (*handler)(void *), void *data)
 {
-	dss_mgr_ops->unregister_framedone_handler(mgr->id, handler, data);
+	dss_mgr_ops->unregister_framedone_handler(channel, handler, data);
 }
 EXPORT_SYMBOL(dss_mgr_unregister_framedone_handler);