pinctrl: at91: make it work with current gpiolib

pinctrl-at91 currently does not support the gpio-groups devicetree
property and has no pin-range.
Because of this at91 gpios stopped working since patch
commit 2ab73c6 ("gpio: Support GPIO controllers without pin-ranges")
This was discussed in the patches
commit fc328a7 ("gpio: Revert regression in sysfs-gpio (gpiolib.c)")
commit 56e337f ("Revert "gpio: Revert regression in sysfs-gpio (gpiolib.c)"")

As a workaround manually set pin-range via gpiochip_add_pin_range() until
a) pinctrl-at91 is reworked to support devicetree gpio-groups
b) another solution as mentioned in
commit 56e337f ("Revert "gpio: Revert regression in sysfs-gpio (gpiolib.c)"")
is found

Signed-off-by: Thomas Blocher <thomas.blocher@ek-dev.de>
Link: https://lore.kernel.org/5b992862-355d-f0de-cd3d-ff99e67a4ff1@ek-dev.de
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: Thomas Blocher

drivers/pinctrl/pinctrl-at91.c

@@ -1403,8 +1403,11 @@ static int at91_pinctrl_probe(struct platform_device *pdev)
 
 	/* We will handle a range of GPIO pins */
 	for (i = 0; i < gpio_banks; i++)
-		if (gpio_chips[i])
+		if (gpio_chips[i]) {
 			pinctrl_add_gpio_range(info->pctl, &gpio_chips[i]->range);
+			gpiochip_add_pin_range(&gpio_chips[i]->chip, dev_name(info->pctl->dev), 0,
+				gpio_chips[i]->range.pin_base, gpio_chips[i]->range.npins);
+		}
 
 	dev_info(dev, "initialized AT91 pinctrl driver\n");