gpio: eic-sprd: unregister from the irq notifier on remove()

gpio: eic-sprd: unregister from the irq notifier on remove()

This is a tristate module, it can be unloaded. We need to cleanup properly
and unregister from the interrupt notifier on driver detach.

Fixes: b32415652a4d ("gpio: eic-sprd: use atomic notifiers to notify all chips about irqs")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>