dm: regulator: support regulator more state

support parse regulator standard property:
regulator-off-in-suspend;
regulator-init-microvolt;
regulator-suspend-microvolt:
 regulator_get_suspend_enable
 regulator_set_suspend_enable
 regulator_get_suspend_value
 regulator_set_suspend_value

Signed-off-by: Joseph Chen <chenjh@rock-chips.com>
Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>