This reduces overhead by accessing cachelines from the wrong node, as well
as simplifying locking.

[Qing: fix for inactive or expired one-shot timer]
Signed-off-by: Yaozu (Eddie) Dong <Eddie.Dong@intel.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>