video: Drop unprintable characters from video_font_data.h

This file contains characters which are not valid in utf-8. This confuses
dtoc which wants to parse it. They don't really serve any purpose anyway,
so drop them.

To: U-Boot Mailing List <u-boot@lists.denx.de>
Cc: Tom Rini <trini@konsulko.com>

Signed-off-by: Simon Glass <sjg@chromium.org>