s390 CVE-2016-2143 whitelist for RHEL kernels

Summary: This patch adds whitelist for RHEL6 and RHEL7 kernels that are known to have the CVE fixed.

Reviewers: koriakin, kcc

Reviewed By: kcc

Subscribers: kubamracek

Differential Revision: https://reviews.llvm.org/D29825

llvm-svn: 294799