xfs: split out attribute listing code into separate file

The attribute listing code is not used by userspace, so like the
directory readdir code, split it out into a separate file to
minimise the differences between the filesystem shared with libxfs
in userspace.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

fs/xfs/xfs_attr.h

@@ -141,5 +141,6 @@ typedef struct xfs_attr_list_context {
  */
 int xfs_attr_inactive(struct xfs_inode *dp);
 int xfs_attr_list_int(struct xfs_attr_list_context *);
+int xfs_inode_hasattr(struct xfs_inode *ip);
 
 #endif	/* __XFS_ATTR_H__ */