drm/bridge: anx6345: set correct BPC for display_info of connector

Some drivers (e.g. sun4i-drm) need this info to decide whether they
need to enable dithering. Currently driver reports what panel supports
and if panel supports 8 we don't get dithering enabled.

Hardcode BPC to 6 for now since that's the only BPC
that driver supports.

Fixes: 6aa19269 ("drm/bridge: Add Analogix anx6345 support")
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Acked-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200329222253.2941405-1-anarsoul@gmail.com

drivers/gpu/drm/bridge/analogix/analogix-anx6345.c

@@ -485,6 +485,9 @@ static int anx6345_get_modes(struct drm_connector *connector)
 
 	num_modes += drm_add_edid_modes(connector, anx6345->edid);
 
+	/* Driver currently supports only 6bpc */
+	connector->display_info.bpc = 6;
+
 unlock:
 	if (power_off)
 		anx6345_poweroff(anx6345);