gpio: exar: Fix bad handling for ida_simple_get error path

The commit 7ecced0 ("gpio: exar: add a check for the return value
of ida_simple_get fails") added a goto jump to the common error
handler for ida_simple_get() error, but this is wrong in two ways:
it doesn't set the proper return code and, more badly, it invokes
ida_simple_remove() with a negative index that shall lead to a kernel
panic via BUG_ON().

This patch addresses those two issues.

Fixes: 7ecced0 ("gpio: exar: add a check for the return value of ida_simple_get fails")
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

drivers/gpio/gpio-exar.c

@@ -148,8 +148,10 @@ static int gpio_exar_probe(struct platform_device *pdev)
 	mutex_init(&exar_gpio->lock);
 
 	index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
-	if (index < 0)
-		goto err_destroy;
+	if (index < 0) {
+		ret = index;
+		goto err_mutex_destroy;
+	}
 
 	sprintf(exar_gpio->name, "exar_gpio%d", index);
 	exar_gpio->gpio_chip.label = exar_gpio->name;
@@ -176,6 +178,7 @@ static int gpio_exar_probe(struct platform_device *pdev)
 
 err_destroy:
 	ida_simple_remove(&ida_index, index);
+err_mutex_destroy:
 	mutex_destroy(&exar_gpio->lock);
 	return ret;
 }