[PATCH 3/4] modify account_system_time() to update guest time in cpustat and task_struct

[PATCH 3/4] modify account_system_time() to add cputime to cpustat->guest if we
are running a VCPU. We add this cputime to  cpustat->user instead of
cpustat->system because this part of KVM code is in fact user code although it
is executed in the kernel. We duplicate VCPU time between guest and user to
allow an unmodified "top(1)" to display correct value. A modified "top(1)" is
able to display good cpu user time and cpu guest time by subtracting cpu guest
time from cpu user time. Update "gtime" in task_struct accordingly.

Signed-off-by: Laurent Vivier <redacted>
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------------- Laurent.Vivier@bull.net  --------------
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