Don't store pointers to regulator_dev returned by
devm_regulator_register() in allocated memory in state container. They
aren't used anywhere outside of max77693_pmic_probe() function.

This change allows removing completely the 'struct max77693_pmic_dev'
state container as none of its fields are used outside of probe.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Mark Brown <broonie@linaro.org>