doc: fix dead kconfig links
doc: fix dead kconfig links

Links to Linux kernel Kconfig documentation are broken, so replace them
with working ones.

Signed-off-by: David Lechner <aa743a0aaec8f7d7a1f01442503957f4d7a2d634@lechnology.com>

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