AVX-512 is an extention of AVX2. Its spec can be found at:
http://download-software.intel.com/sites/default/files/managed/71/2e/319433-017.pdf

This patch detects AVX-512 features by CPUID.
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1392931491-33237-1-git-send-email-fenghua.yu@intel.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org> # hw enabling