gpio: emulated: default Kconfig value
gpio: emulated: default Kconfig value

Enable the emulated GPIO driver by default if instances exist in
devicetree. This removes the need to manually enable `CONFIG_GPIO_EMUL`
when `CONFIG_GPIO` is enabled.

Signed-off-by: Jordan Yates <d74a90e280bbad1cc3646781a4e234b467b60fe1@data61.csiro.au>

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