cgroup: Remove steal time from usage_usec

The CPU usage time is the time when user, system or both are using the CPU.
Steal time is the time when CPU is waiting to be run by the Hypervisor. It
should not be added to the CPU usage time, hence removing it from the
usage_usec entry.

Fixes: 936f2a7 ("cgroup: add cpu.stat file to root cgroup")
Acked-by: Axel Busch <axel.busch@ibm.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Muhammad Adeel <muhammad.adeel@ibm.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Author: madeelibm

kernel/cgroup/rstat.c

@@ -590,7 +590,6 @@ static void root_cgroup_cputime(struct cgroup_base_stat *bstat)
 
 		cputime->sum_exec_runtime += user;
 		cputime->sum_exec_runtime += sys;
-		cputime->sum_exec_runtime += cpustat[CPUTIME_STEAL];
 
 #ifdef CONFIG_SCHED_CORE
 		bstat->forceidle_sum += cpustat[CPUTIME_FORCEIDLE];