reset: Add driver for gpio-controlled reset pins

This driver implements a reset controller device that toggle a gpio
connected to a reset pin of a peripheral IC. The delay between assertion
and de-assertion of the reset signal can be configured via device tree.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
gpio: 75x164: deassert the device from reset

Some of these devices might be asserted is reset by pulling down the MR
pin. Add support for the reset framework API to deassert these devices
from reset if the resets property is found in the device tree.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>