erofs: set iowait for sync decompression

For those tasks waiting I/O for sync decompression,
they should be better marked as IO wait state.

Link: https://lore.kernel.org/r/20191008125616.183715-5-gaoxiang25@huawei.comReviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>

fs/erofs/zdata.c

@@ -1288,7 +1288,7 @@ static void z_erofs_submit_and_unzip(struct super_block *sb,
 		return;
 
 	/* wait until all bios are completed */
-	wait_event(io[JQ_SUBMIT].u.wait,
+	io_wait_event(io[JQ_SUBMIT].u.wait,
 		      !atomic_read(&io[JQ_SUBMIT].pending_bios));
 
 	/* let's synchronous decompression */