power: Add simple gpio-restart driver

This driver registers a restart handler to set a GPIO line high/low
to reset a board based on devicetree bindings.

Signed-off-by: David Riley <davidriley@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>

drivers/power/reset/Kconfig

@@ -39,6 +39,14 @@ config POWER_RESET_GPIO
 	  If your board needs a GPIO high/low to power down, say Y and
 	  create a binding in your devicetree.
 
+config POWER_RESET_GPIO_RESTART
+	bool "GPIO restart driver"
+	depends on OF_GPIO && POWER_RESET
+	help
+	  This driver supports restarting your board via a GPIO line.
+	  If your board needs a GPIO high/low to restart, say Y and
+	  create a binding in your devicetree.
+
 config POWER_RESET_HISI
 	bool "Hisilicon power-off driver"
 	depends on POWER_RESET && ARCH_HISI