reset: gpio: Add GPIO-based reset controller

Add a simple driver to control GPIO-based resets using the reset
controller API for the cases when the GPIOs are shared and reset should
be coordinated.  The driver is expected to be used by reset core
framework for ad-hoc reset controllers.

Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Cc: Sean Anderson <sean.anderson@seco.com>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240129115216.96479-4-krzysztof.kozlowski@linaro.org


Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>