Remove unnecessary bit shifts.
Correct min value to match datasheet.
Num steps = number of steps between min and max.
Reported-by: Ryan Harvey <ryan.harvey@cirrus.com> Signed-off-by: Ryan Harvey <ryan.harvey@cirrus.com> Signed-off-by: Brian Austin <brian.austin@cirrus.com> Signed-off-by: Mark Brown <broonie@linaro.org>