Add vfa/vfs/vfm/vfd support on s390

R=joransiu@ca.ibm.com, bjaideep@ca.ibm.com, danno@chromium.org, jkummerow@chromium.org, jochen@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2582683002
Cr-Commit-Position: refs/heads/master@{#41741}