Revert "f2fs: updates from 3.15"

This reverts commit 45deb156fb5257aa163e64716cb9522dad7fef46.
Revert "f2fs: Update to version in 3.14"

This reverts commit 8b3f2b5bae2eea711edf977f49694290790152ca.

Conflicts:
	fs/f2fs/data.c
Revert "F2FS: Backport to 3.4"

This reverts commit a16994199d5a256202021aacf28885eabde602bd.