staging: exfat: remove exfat_buf_sync()

exfat_buf_sync() is not called anywhere, hence remove it from
exfat_cache.c and exfat.h
Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
Link: https://lore.kernel.org/r/20200223191623.GA20122@kaaira-HP-Pavilion-NotebookSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/exfat/exfat.h

@@ -653,7 +653,6 @@ void exfat_buf_lock(struct super_block *sb, sector_t sec);
 void exfat_buf_unlock(struct super_block *sb, sector_t sec);
 void exfat_buf_release(struct super_block *sb, sector_t sec);
 void exfat_buf_release_all(struct super_block *sb);
-void exfat_buf_sync(struct super_block *sb);
 
 /* fs management functions */
 void fs_set_vol_flags(struct super_block *sb, u32 new_flag);

drivers/staging/exfat/exfat_cache.c

@@ -515,22 +515,3 @@ void exfat_buf_release_all(struct super_block *sb)
 
 	mutex_unlock(&b_mutex);
 }
-
-void exfat_buf_sync(struct super_block *sb)
-{
-	struct buf_cache_t *bp;
-	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
-
-	mutex_lock(&b_mutex);
-
-	bp = p_fs->buf_cache_lru_list.next;
-	while (bp != &p_fs->buf_cache_lru_list) {
-		if ((bp->drv == p_fs->drv) && (bp->flag & DIRTYBIT)) {
-			sync_dirty_buffer(bp->buf_bh);
-			bp->flag &= ~(DIRTYBIT);
-		}
-		bp = bp->next;
-	}
-
-	mutex_unlock(&b_mutex);
-}