[PATCH] dix: use BUG_WARN for xi2mask size issues

[Peter Hutterer]

> @@ -990,8 +991,9 @@ xi2mask_isset(XI2Mask* mask, const DeviceIntPtr dev, int event_type)
>   void
>   xi2mask_set(XI2Mask *mask, int deviceid, int event_type)
>   {
> -    if (deviceid<  0 || deviceid>= mask->nmasks || event_type>= mask->mask_size)
> -        return;
> +    BUG_WARN(devicid<  0);

I should probably mention that I did fix that one locally but forgot to 
squash before sending the patch.