[GFS2] use the declaration of gfs2_dops in the header file instead

#include "lm.h"

#include "mount.h"

#include "ops_fstype.h"

#include "ops_dentry.h"

#include "ops_super.h"

#include "recovery.h"

#include "rgrp.h"

#define DO 0

#define UNDO 1

extern struct dentry_operations gfs2_dops;

static struct gfs2_sbd *init_sbd(struct super_block *sb)

{

	struct gfs2_sbd *sdp;