regulator: gpio: add gpios-status for DT

config->gpios[x].flags indicates initial pin status,
and it will be used for drvdata->state
on gpio_regulator_probe().
But, current of_get_gpio_regulator_config() doesn't care
about this flags.
This patch adds new gpios-status property in order to
care about initial pin status.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@linaro.org>