hpfs: switch to ->iterate_shared()

NOTE: the only reason we can do that without ->i_rdir_offs races
is that hpfs_lock() serializes everything in there anyway. It's
not that hard to get rid of, but not as part of this series...

Signed-off-by: Al Viro <[e-mail]>

fs/hpfs/dir.c

···
 {
 	.llseek		= hpfs_dir_lseek,
 	.read		= generic_read_dir,
-	.iterate	= hpfs_readdir,
+	.iterate_shared	= hpfs_readdir,
 	.release	= hpfs_dir_release,
 	.fsync		= hpfs_file_fsync,
 	.unlocked_ioctl	= hpfs_ioctl,