It's not clear what a sink would do if you wrote zero to this register -
which I guess would mean "I don't support any channel encodings, good
luck" - but let's not find out.
Signed-off-by: Adam Jackson <ajax@redhat.com> Reviewed-by: Keith Packard <keithp@keithp.com> Signed-off-by: Keith Packard <keithp@keithp.com>