ocfs2: remove unused declaration in header file

The definition of ocfs2_global_read_dquot() has been removed since commit
fb8dd8d78014 ("ocfs2: Fix quota locking"). Let's remove the empty
declartion

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Zhang Zekun <[e-mail]>
Cc: Mark Fasheh <[e-mail]>
Cc: Joel Becker <[e-mail]>
Cc: Junxiao Bi <[e-mail]>
Cc: Joseph Qi <[e-mail]>
Cc: Changwei Ge <[e-mail]>
Cc: Jun Piao <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

fs/ocfs2/quota.h

···
 			  const char *data, size_t len, loff_t off);
 int ocfs2_global_read_info(struct super_block *sb, int type);
 int ocfs2_global_write_info(struct super_block *sb, int type);
-int ocfs2_global_read_dquot(struct dquot *dquot);
 int __ocfs2_sync_dquot(struct dquot *dquot, int freeing);
 static inline int ocfs2_sync_dquot(struct dquot *dquot)
 {