[S390] cpu hotplug and accounting values

Reset the cpu timer to the maximum value and correctly initialize the
cpu accounting values in the lowcore when the cpu is started.

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

diff --cc arch/s390/kernel/asm-offsets.c
Simple merge

diff --cc arch/s390/kernel/entry.S
Simple merge

diff --cc arch/s390/kernel/entry64.S
Simple merge