gpio: synq: remove unused zynq_gpio_irq_reqres/zynq_gpio_irq_relres

The driver now uses the generic request/release callbacks, so the custom
ones are no longer called. When building with -Woverride-init, gcc produces
a warning about the duplicate entries:

In file included from drivers/gpio/gpio-zynq.c:10:
include/linux/gpio/driver.h:621:43: error: initialized field overwritten [-Werror=override-init]
  621 |                 .irq_request_resources  = gpiochip_irq_reqres,          \
      |                                           ^~~~~~~~~~~~~~~~~~~
drivers/gpio/gpio-zynq.c:611:9: note: in expansion of macro 'GPIOCHIP_IRQ_RESOURCE_HELPERS'
  611 |         GPIOCHIP_IRQ_RESOURCE_HELPERS,
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/gpio/driver.h:621:43: note: (near initialization for 'zynq_gpio_level_irqchip.irq_request_resources')
  621 |                 .irq_request_resources  = gpiochip_irq_reqres,          \
      |                                           ^~~~~~~~~~~~~~~~~~~
drivers/gpio/gpio-zynq.c:625:9: note: in expansion of macro 'GPIOCHIP_IRQ_RESOURCE_HELPERS'
  625 |         GPIOCHIP_IRQ_RESOURCE_HELPERS,
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/gpio/driver.h:622:43: error: initialized field overwritten [-Werror=override-init]
  622 |                 .irq_release_resources  = gpiochip_irq_relres
      |                                           ^~~~~~~~~~~~~~~~~~~

Removing the old ones has no effect on the driver but avoids the warnings.

Fixes: f5691439 ("gpio: zynq: fix zynqmp_gpio not an immutable chip warning")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>