unified/sysgen: do not generate TICK_EVENT event
unified/sysgen: do not generate TICK_EVENT event

Sysgen was still generating the TICK_EVENT event needed for the
microkernel system clock timer driver in the unified kernel. That ended
up dragging in alerts all the time, which in turns drag in the system
work queue, which drags in the work queue, which drags in FIFOs.

This shaves 1052 bytes of RAM and 860 bytes of ROM in systems that don't
need these components (on x86 with IAMCU).

Change-Id: Ica56857da2b6444181f10e83f6c986d092aa967b
Signed-off-by: Benjamin Walsh <578db18f23ec223e50c404886c947386478a464e@windriver.com>

zephyriot/zephyr,runchip/zephyr-cc3220,bigdinotech/zephyr,ldts/zephyr,erwango/zephyr,Vudentz/zephyr,galak/zephyr,explora26/zephyr,runchip/zephyr-cc3220,zephyriot/zephyr,finikorg/zephyr,bboozzoo/zephyr,nashif/zephyr,explora26/zephyr,runchip/zephyr-cc3200,fbsder/zephyr,holtmann/zephyr,fractalclone/zephyr-riscv,fractalclone/zephyr-riscv,nashif/zephyr,pklazy/zephyr,Vudentz/zephyr,holtmann/zephyr,zephyrproject-rtos/zephyr,fractalclone/zephyr-riscv,nashif/zephyr,pklazy/zephyr,bboozzoo/zephyr,zephyriot/zephyr,punitvara/zephyr,bboozzoo/zephyr,erwango/zephyr,fractalclone/zephyr-riscv,ldts/zephyr,punitvara/zephyr,runchip/zephyr-cc3200,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,pklazy/zephyr,Vudentz/zephyr,aceofall/zephyr-iotos,mbolivar/zephyr,punitvara/zephyr,erwango/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,bigdinotech/zephyr,sharronliu/zephyr,kraj/zephyr,fbsder/zephyr,runchip/zephyr-cc3220,tidyjiang8/zephyr-doc,holtmann/zephyr,Vudentz/zephyr,sharronliu/zephyr,galak/zephyr,explora26/zephyr,runchip/zephyr-cc3200,pklazy/zephyr,runchip/zephyr-cc3200,pklazy/zephyr,fbsder/zephyr,GiulianoFranchetto/zephyr,aceofall/zephyr-iotos,bboozzoo/zephyr,finikorg/zephyr,rsalveti/zephyr,ldts/zephyr,bboozzoo/zephyr,tidyjiang8/zephyr-doc,sharronliu/zephyr,mbolivar/zephyr,GiulianoFranchetto/zephyr,kraj/zephyr,zephyrproject-rtos/zephyr,bigdinotech/zephyr,fbsder/zephyr,finikorg/zephyr,fractalclone/zephyr-riscv,Vudentz/zephyr,fbsder/zephyr,aceofall/zephyr-iotos,zephyriot/zephyr,erwango/zephyr,explora26/zephyr,nashif/zephyr,finikorg/zephyr,punitvara/zephyr,zephyriot/zephyr,holtmann/zephyr,punitvara/zephyr,rsalveti/zephyr,runchip/zephyr-cc3220,rsalveti/zephyr,kraj/zephyr,galak/zephyr,sharronliu/zephyr,nashif/zephyr,aceofall/zephyr-iotos,tidyjiang8/zephyr-doc,ldts/zephyr,Vudentz/zephyr,galak/zephyr,runchip/zephyr-cc3200,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,bigdinotech/zephyr,erwango/zephyr,kraj/zephyr,rsalveti/zephyr,galak/zephyr,kraj/zephyr,aceofall/zephyr-iotos,bigdinotech/zephyr,tidyjiang8/zephyr-doc,mbolivar/zephyr,tidyjiang8/zephyr-doc,mbolivar/zephyr,runchip/zephyr-cc3220,sharronliu/zephyr,ldts/zephyr,rsalveti/zephyr,holtmann/zephyr,mbolivar/zephyr