gpio: fix memory and reference leaks in gpiochip_add error path

commit 5539b3c9 upstream.

Memory allocated and references taken by of_gpiochip_add and
acpi_gpiochip_add were never released on errors in gpiochip_add (e.g.
failure to find free gpio range).

Fixes: 391c970c ("of/gpio: add default of_xlate function if device
has a node pointer")
Fixes: 664e3e5a ("gpio / ACPI: register to ACPI events
automatically")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[bwh: Backported to 3.2:
 - Move call to of_gpiochip_add() into conditional section rather
   than rearranging gotos and labels which are in different places
   here
 - There's no ACPI support]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/gpio/gpiolib.c

@@ -1075,9 +1075,9 @@ int gpiochip_add(struct gpio_chip *chip)
 				? (1 << FLAG_IS_OUT)
 				: 0;
 		}
-	}
 
-	of_gpiochip_add(chip);
+		of_gpiochip_add(chip);
+	}
 
 unlock:
 	spin_unlock_irqrestore(&gpio_lock, flags);
@@ -1086,8 +1086,10 @@ int gpiochip_add(struct gpio_chip *chip)
 		goto fail;
 
 	status = gpiochip_export(chip);
-	if (status)
+	if (status) {
+		of_gpiochip_remove(chip);
 		goto fail;
+	}
 
 	return 0;
 fail: