drm/omap: remove extra check in dpi and sdi

Both dpi and sdi check for 'mgr != NULL' in check_timings. This check is
not necessary, as mgr must always be set before check_timings. Remove
the check.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/gpu/drm/omapdrm/dss/dpi.c

@@ -516,7 +516,7 @@ static int dpi_check_timings(struct omap_dss_device *dssdev,
 	if (timings->x_res % 8 != 0)
 		return -EINVAL;
 
-	if (mgr && !dispc_mgr_timings_ok(mgr->id, timings))
+	if (!dispc_mgr_timings_ok(mgr->id, timings))
 		return -EINVAL;
 
 	if (timings->pixelclock == 0)

drivers/gpu/drm/omapdrm/dss/sdi.c

@@ -244,7 +244,7 @@ static int sdi_check_timings(struct omap_dss_device *dssdev,
 {
 	struct omap_overlay_manager *mgr = sdi.output.manager;
 
-	if (mgr && !dispc_mgr_timings_ok(mgr->id, timings))
+	if (!dispc_mgr_timings_ok(mgr->id, timings))
 		return -EINVAL;
 
 	if (timings->pixelclock == 0)