mfd: max8925: Remove array in regulator platform data

Remove array in parent's platform data. Use struct regulator_init_data
as regulator device's platform data directly. So a lot of pdata are
added into parent's platform data. And voltage out register offset
is used as IORESOURCE_REG to distinguish different regualtor devices.

Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>