Previously the ioctl-based configuration was not encoded properly.
It lacked the three command bits selecting the "set volatile
configuration" mode.
Thus, configuration the reference, power-down or gain resulted in no
change.
Now the configuration is properly applied.
The DAC value to be send is now combined with the proper command prefix
bits, too.
But this operation was already working, since the command prefix is zero.
Signed-off-by: Lars Kruse <devel@sumpfralle.de>
Lars Kruse
21c19b7824