debug: tracing: Fix compilation error
debug: tracing: Fix compilation error

This commit adds the kernel.h include in order to provide
sys_clock_hw_cycles_per_sec() declaration.

Signed-off-by: Piotr Zięcik <9ef3595b5f0f4fa8d0ceeb52cc0cf0411a0684dd@nordicsemi.no>

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