arch: x86: core: include kernel.h first
arch: x86: core: include kernel.h first

There seems to be an unresolved dependency chain in some x86 arch
headers, this file needs kernel.h to be included before arch_data/func.
This patch is a workaround, but problem should be fixed properly at some
point.

Signed-off-by: Gerard Marull-Paretas <bedb45f43a286e49f4dcda039a436b216ae61ef3@nordicsemi.no>

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