gpio: zynq: restore zynq_gpio_irq_reqres/zynq_gpio_irq_relres callbacks

Commit f5691439

 ("gpio: zynq: fix zynqmp_gpio not an immutable chip
warning") ditched the open-coded resource allocation handlers in favor
of the generic ones. These generic handlers don't maintain the PM
runtime anymore, which causes a regression in that level IRQs are no
longer reported.

Restore the original handlers to fix this.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Fixes: f5691439

 ("gpio: zynq: fix zynqmp_gpio not an immutable chip warning")
Cc: stable@kernel.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>