f2fs: trigger release_dirty_inode in f2fs_put_super

The generic_shutdown_super calls sync_filesystem, evict_inode, and then
f2fs_put_super. In f2fs_evict_inode, we remain some dirty inode information
so we should release them at f2fs_put_super.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/super.c

@@ -435,6 +435,9 @@ static void f2fs_put_super(struct super_block *sb)
 	if (sbi->s_dirty)
 		write_checkpoint(sbi, true);
 
+	/* normally superblock is clean, so we need to release this */
+	release_dirty_inode(sbi);
+
 	iput(sbi->node_inode);
 	iput(sbi->meta_inode);