[S390] Fix timeval regression on s390

commit aa5e97ce4bbc9d5daeec16b1d15bb3f6b7b4f4d4
[PATCH] improve precision of process accounting.

Introduced a timing regression:
-bash-3.2# time ls
real 0m0.006s
user 0m1.754s
sys 0m1.094s

The problem was introduced by an error in cputime_to_timeval.
Cputime is now 1/4096 microsecond, therefore, we have to divide
the remainder with 4096 to get the microseconds.

Signed-off-by: Christian Borntraeger <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/include/asm/cputime.h

···
 	value->tv_usec = rp.subreg.even / 4096;
 	value->tv_sec = rp.subreg.odd;
 #else
-	value->tv_usec = cputime % 4096000000ULL;
+	value->tv_usec = (cputime % 4096000000ULL) / 4096;
 	value->tv_sec = cputime / 4096000000ULL;
 #endif
 }