Move prototypes and in-core structures to fs/ufs/ similar to what most
other filesystems already do.

I made little modifications: move also ufs debug macros and
mount options constants into fs/ufs/ufs.h, this stuff
also private for ufs.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NEvgeniy Dushistov <dushistov@mail.ru>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>