regulator: s5m8767: Do not use sec_reg* regmap helpers

Replace calls to sec_reg* helpers with direct usage of regmap API. The
sec_reg* helpers are error-prone as they mix u8 with unsigned int and
order of some of parameters (val and mask in sec_reg_update()).

Also the helpers do not give any way of useful abstraction as they just
call corresponding regmap function.

This patch replaces:
 - sec_reg_read() with regmap_read(),
 - sec_reg_write() with regmap_write(),
 - sec_reg_update() with regmap_update_bits().

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>