[GFS2] Remove unused declaration

The implementation of gfs2_inode_attr_in is removed.
So remove its declaration.
Signed-off-by: NLi Xiaodong <lixd@cn.fujitsu.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/inode.h

@@ -72,7 +72,6 @@ static inline void gfs2_inum_out(const struct gfs2_inode *ip,
 }
 
 
-void gfs2_inode_attr_in(struct gfs2_inode *ip);
 void gfs2_set_iop(struct inode *inode);
 struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned type, 
 				u64 no_addr, u64 no_formal_ino,