This patch converts .is_enabled and .get_voltage_sel to
regulator_is_enabled_regmap and regulator_get_voltage_sel_regmap.

For .enable, .disable, and .set_voltage_sel, the write protect level is either
1 or 2. So we cannot use regulator_[enable|disable|set_voltage_sel]_regmap.

Now we store the enable reg/mask and vsel reg/mask in regulator_desc,
so we can remove enable_mask, set_vout_reg, and set_vout_mask from
struct tps_info.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>