fs/ufs/super.c: remove unnecessary casting

Fix the following coccinelle warning:

  fs/ufs/super.c:1418:7-28: WARNING: casting value returned by memory allocation function to (struct ufs_inode_info *) is useless.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Evgeniy Dushistov <dushistov@mail.ru>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>