drm/bridge: tc358767: don't warn if display side ASSR enable fails

ASSR is an optional feature, so it's a valid operating condition for
the display to reject ASSR enable. Demote the warning to the debug
level.

Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by:Andrey Gusakov <andrey.gusakov@cogentembedded.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20161130114810.3245-1-l.stach@pengutronix.de

drivers/gpu/drm/bridge/tc358767.c

@@ -908,7 +908,7 @@ static int tc_main_link_setup(struct tc_data *tc)
 			goto err_dpcd_read;
 
 		if (tmp[0] != tc->assr) {
-			dev_warn(dev, "Failed to switch display ASSR to %d, falling back to unscrambled mode\n",
+			dev_dbg(dev, "Failed to switch display ASSR to %d, falling back to unscrambled mode\n",
 				 tc->assr);
 			/* trying with disabled scrambler */
 			tc->link.scrambler_dis = 1;