fs: import f2fs from git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git (branch dev)

Up-to-date with
git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git @695fd1ed3bcaae9fc032cbe47f0fe9a934bf1717
(f2fs: use existing macro to clean up some codes)

Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com>
f2fs: support 3.4

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Add f2fs updater
fs: rework f2fs
fs: rework f2fs
fs: rework f2fs
fs: rework f2fs