vfs: make get_sb_pseudo set s_maxbytes to value that can be cast to signed

get_sb_pseudo sets s_maxbytes to ~0ULL which becomes negative when cast
to a signed value.  Fix it to use MAX_LFS_FILESIZE which casts properly
to a positive signed value.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Steve French <smfrench@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Robert Love <rlove@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>