drm/omap: convert dss_mgr_enable to accept omap_channel

We are removing uses of 'struct omap_overlay_manager'. This patch
changes dss_mgr_enable() 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/hdmi4.c

@@ -219,7 +219,7 @@ static int hdmi_power_on_full(struct omap_dss_device *dssdev)
 	/* tv size */
 	dss_mgr_set_timings(mgr->id, p);
 
-	r = dss_mgr_enable(mgr);
+	r = dss_mgr_enable(mgr->id);
 	if (r)
 		goto err_mgr_enable;