staging: Solo6x10: Build MPEG4 headers on the fly.

This will make them maintainable. Also, it now works on big-endian systems.

This is the slow path (done every 1+ second, per channel) so I guess
there is no need to cache the results.

I have removed CBR-related bits from the MPEG4 VOL header since we can't
do CBR (at least yet).

Signed-off-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>