gpio: export devm_gpio_request_one

Without this, modules can't use this API, leading to build failures.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/devres.c

@@ -98,6 +98,7 @@ int devm_gpio_request_one(struct device *dev, unsigned gpio,
 
 	return 0;
 }
+EXPORT_SYMBOL(devm_gpio_request_one);
 
 /**
  *      devm_gpio_free - free an interrupt