Revert "f2fs: remove unreachable lazytime mount option parsing"

commit acff9409 upstream.

This reverts commit 54f43a10.

The above commit broke the lazytime mount, given

mount("/dev/vdb", "/mnt/test", "f2fs", 0, "lazytime");

CC: stable@vger.kernel.org # 6.11+
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>