soc: nrf: fix NRF_DT_CHECK_GPIO_CTLR_IS_SOC
soc: nrf: fix NRF_DT_CHECK_GPIO_CTLR_IS_SOC

This was merged by mistake without being tested and is not working
properly. We need to avoid doing a BUILD_ASSERT() when the relevant
property is missing, because we can't use DT_GPIO_CTLR() on an
undefined property. Handle this with COND_CODE_1().

Signed-off-by: Martí Bolívar <9d90ac4c7bf6a305f6bfd81a23c7859bc883380e@nordicsemi.no>

Vudentz/zephyr,galak/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,nashif/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,nashif/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr