EPT table can be changed concurrently by more than one vcpus.
This patch add a lock to protect the add/modify/delete operations
from different vcpus concurrently.
Tracked-On: #4253
Signed-off-by: Jian Jun Chen <jian.jun.chen@intel.com>
Reviewed-by: Li, Fei1 <fei1.li@intel.com>