mfd: Correct WM831X_MAX_ISEL_VALUE

There was confusion between the array size and the highest ISEL
value possible.

Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2 files changed