gandof: modify audio volume curve for headphone

adjust headphone volume_step, apply volume_step 70 instead of current
value 50.

TEST=`emerge-gandof adhd` verify file is modified.
BUG=chrome-os-partner:39168
Signed-off-by: Pan Sheng-Liang <Sheng-Liang.Pan@quantatw.com>

Change-Id: Ibd7382a2161ed50d42824348507937d7dff852ca
Reviewed-on: https://chromium-review.googlesource.com/285000
Reviewed-by: Yomyung Leem <yungleem@chromium.org>
Commit-Queue: David Wu <david_wu@quantatw.com>
Tested-by: David Wu <david_wu@quantatw.com>
1 file changed