winex11: Add a few 'fall through' comments.

[Dmitry Timoshkov]

Huw Davies <huw at codeweavers.com> wrote:

>      case DirectColor:
>  	X11DRV_PALETTE_PaletteFlags |= X11DRV_PALETTE_VIRTUAL;
> -    case GrayScale:
> +    case GrayScale: /* fall through */

    case DirectColor:
	X11DRV_PALETTE_PaletteFlags |= X11DRV_PALETTE_VIRTUAL;
        /* fall through */
    case GrayScale:

would be more clear IMHO. Right now it's not obvious to which case statement
'fall through' belongs to.

Same for other changes.

-- 
Dmitry.