1. move out vm related code from arch/pm.
2. remove unnecssary global variables.
3. keep the global variables as static, not used
by other modules directlly.
Tracked-On: #1842
Signed-off-by: Minggui Cao <minggui.cao@intel.com>
Reviewed-by: Victor Sun <victor.sun@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>