If Supervisor Mode Access Prevention is available and not disabled by
the user, turn it on.  Also fix the expansion of SMEP (Supervisor Mode
Execution Prevention.)
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1348256595-29119-10-git-send-email-hpa@linux.intel.com