gpio: zynq: Fix wakeup source leaks on device unbind

Device can be unbound, so driver must also release memory for the wakeup
source.

Cc: stable@vger.kernel.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250406202245.53854-2-krzysztof.kozlowski@linaro.org


Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>