Revert "FS: import F2FS"

This reverts commit fad9b240738603626adb7b00c4fb64de24a6b0b2.
fs: add support for f2fs

this is the current state of importing(just for merging fixes from upstream):
http://git.kernel.org/cgit/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=linux-3.4&id=1bb1af07b03d3e65c02a452aff747efd4390c74c