DO NOT MERGE New ext4enc kernel switching from xattrs to ioctl

(cherry-picked from change f7163597f595435f90f4f50cfae38ef0dd01a21b)

This is one of three changes to enable this functionality:
  https://android-review.googlesource.com/#/c/146259/
  https://android-review.googlesource.com/#/c/146264/
  https://android-review.googlesource.com/#/c/146265/

Bug: 18151196

Change-Id: I6ce4bc977a548df93ea5c09430f93eef5ee1f9fa
3 files changed