gpio: Enable nonexclusive gpiods from DT nodes

This makes gpiod_get_from_of_node() respect the
GPIOD_FLAGS_BIT_NONEXCLUSIVE flag which is especially
nice when getting regulator GPIOs right out of device
tree nodes.

Suggested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Fixes: b0ce7b2 ("regulator/gpio: Allow nonexclusive GPIO access")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/gpio/gpiolib.c

@@ -4204,6 +4204,8 @@ struct gpio_desc *gpiod_get_from_of_node(struct device_node *node,
  transitory = flags & OF_GPIO_TRANSITORY;
 
  ret = gpiod_request(desc, label);
+ if (ret == -EBUSY && (flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
+ return desc;
  if (ret)
  return ERR_PTR(ret);