xfs: move declaration to header file

Fix this sparse warning:
  fs/xfs/xfs_da_btree.c:1550:26: warning: symbol 'xfs_default_nameops' was not declared. Should it be static?

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Felix Blyakher <felixb@sgi.com>

fs/xfs/xfs_da_btree.h

@@ -268,5 +268,6 @@ xfs_daddr_t xfs_da_blkno(xfs_dabuf_t *dabuf);
 
 extern struct kmem_zone *xfs_da_state_zone;
 extern struct kmem_zone *xfs_dabuf_zone;
+extern const struct xfs_nameops xfs_default_nameops;
 
 #endif	/* __XFS_DA_BTREE_H__ */

fs/xfs/xfs_dir2.c

@@ -46,8 +46,6 @@
 
 struct xfs_name xfs_name_dotdot = {"..", 2};
 
-extern const struct xfs_nameops xfs_default_nameops;
-
 /*
  * ASCII case-insensitive (ie. A-Z) support for directories that was
  * used in IRIX.