extcon: qcom-spmi-misc: Fix wakeup source leaks on device unbind

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

Link: https://lore.kernel.org/lkml/20250501-device-wakeup-leak-extcon-v2-4-7af77802cbea@linaro.org/


Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>