gpio: exar: add a check for the return value of ida_simple_get fails

ida_simple_get may fail and return a negative error number.
The fix checks its return value; if it fails, go to err_destroy.

Cc: <[e-mail]>
Signed-off-by: Kangjie Lu <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/gpio-exar.c

···
 	mutex_init(&exar_gpio->lock);
 
 	index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
+	if (index < 0)
+		goto err_destroy;
 
 	sprintf(exar_gpio->name, "exar_gpio%d", index);
 	exar_gpio->gpio_chip.label = exar_gpio->name;