[PATCH] minix v3: fix superblock definition

Somehow we got the layout of the v3 superblock wrong, which causes crashes due
to overindexing of the buffer_head array in statfs on large fielsystems.

Cc: "Cedric Augonnet" <cedric.augonnet@gmail.com>
Cc: "Daniel Aragones" <danarag@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>