[S390] profile_tick called twice

[S390] profile_tick called twice

profile_tick is called twice for every clock comparator interrupt.
The generic clock event code does it in tick_sched_timer and the
s390 backend code in clock_comparator_work. That is one too many,
remove the one in the arch backend code.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>