Headphone volume adjustment

[James Cameron]

This behaviour is coded in rt5631.c ... the codec registers for
speaker and headphones have different dB ranges and we use the same
value in both registers, with the low end truncated.

http://dev.laptop.org/git/olpc-kernel/tree/sound/soc/codecs/rt5631.c?h=arm-3.5#n364
http://dev.laptop.org/git/olpc-kernel/tree/sound/soc/codecs/rt5631.c?h=arm-3.5#n322

-- 
James Cameron
http://quozl.linux.org.au/