gpiolib-acpi: remove unused variable 'err', cleans up build warning

Variable err is defined but never used. Remove it. Cleans up warning:

warning: unused variable ‘err’ [-Wunused-variable]
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpiolib-acpi.c

@@ -882,7 +882,6 @@ acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
 		if (!found) {
 			enum gpiod_flags flags = acpi_gpio_to_gpiod_flags(agpio);
 			const char *label = "ACPI:OpRegion";
-			int err;
 
 			desc = gpiochip_request_own_desc(chip, pin, label,
 							 flags);