drm/omap: convert dss_mgr_disable to accept omap_channel

We are removing uses of 'struct omap_overlay_manager'. This patch
changes dss_mgr_disable() 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/omapdss.h b/drivers/gpu/drm/omapdrm/dss/omapdss.h
index c76802d..25c3449 100644
--- a/drivers/gpu/drm/omapdrm/dss/omapdss.h
+++ b/drivers/gpu/drm/omapdrm/dss/omapdss.h
@@ -91,7 +91,7 @@
 void dss_mgr_set_lcd_config(enum omap_channel channel,
 		const struct dss_lcd_mgr_config *config);
 int dss_mgr_enable(enum omap_channel channel);
-void dss_mgr_disable(struct omap_overlay_manager *mgr);
+void dss_mgr_disable(enum omap_channel channel);
 void dss_mgr_start_update(struct omap_overlay_manager *mgr);
 int dss_mgr_register_framedone_handler(struct omap_overlay_manager *mgr,
 		void (*handler)(void *), void *data);