s390/vtime: correct scaled cputime of partially idle CPUs

The calculation for the SMT scaling factor for a hardware thread
which has been partially idle needs to disregard the cycles spent
by the other threads of the core while the thread is idle.

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/vtime.c
Simple merge