ocfs2: fix undefined struct variable in inode.h

The extern struct variable ocfs2_inode_cache is not defined. It meant to
use ocfs2_inode_cachep defined in super.c, I think. Fortunately it is
not used anywhere now, so no impact actually. Clean it up to fix this
mistake.

Link: http://lkml.kernel.org/r/57E1E49D.8050503@huawei.com
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Eric Ren <zren@suse.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/inode.h

@@ -123,8 +123,6 @@ static inline struct ocfs2_inode_info *OCFS2_I(struct inode *inode)
 #define INODE_JOURNAL(i) (OCFS2_I(i)->ip_flags & OCFS2_INODE_JOURNAL)
 #define SET_INODE_JOURNAL(i) (OCFS2_I(i)->ip_flags |= OCFS2_INODE_JOURNAL)
 
-extern struct kmem_cache *ocfs2_inode_cache;
-
 extern const struct address_space_operations ocfs2_aops;
 extern const struct ocfs2_caching_operations ocfs2_inode_caching_ops;