commit fd694733 upstream.

This patch fixes the bug which does not cover a large section case when checking
the sanity of superblock.
If f2fs detects misalignment, it will fix the superblock during the mount time,
so it doesn't need to trigger fsck.f2fs further.
Reported-by: Matthias Prager <linux@matthiasprager.de>
Reported-by: David Gnedt <david.gnedt@davizone.at>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>