gpiolib: acpi: Move non-critical code outside of critical section

Mika noticed that some code is run under mutex when it doesn't require
the lock, like an error code assignment.

Move non-critical code outside of critical section.

Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>