OMAPDSS: clean up dss_[ovl|mgr]_get_device()

Minor cleanup for the dss_[ovl|mgr]_get_device() functions to make them
more readable.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap2/dss/apply.c

@@ -420,16 +420,14 @@ static void wait_pending_extra_info_updates(void)
 		DSSWARN("timeout in wait_pending_extra_info_updates\n");
 }
 
-static inline struct omap_dss_device *dss_ovl_get_device(struct omap_overlay *ovl)
+static struct omap_dss_device *dss_mgr_get_device(struct omap_overlay_manager *mgr)
 {
-	return ovl->manager ?
-		(ovl->manager->output ? ovl->manager->output->device : NULL) :
-		NULL;
+	return mgr->output ? mgr->output->device : NULL;
 }
 
-static inline struct omap_dss_device *dss_mgr_get_device(struct omap_overlay_manager *mgr)
+static struct omap_dss_device *dss_ovl_get_device(struct omap_overlay *ovl)
 {
-	return mgr->output ? mgr->output->device : NULL;
+	return ovl->manager ? dss_mgr_get_device(ovl->manager) : NULL;
 }
 
 static int dss_mgr_wait_for_vsync(struct omap_overlay_manager *mgr)