bus: sunxi-rsb: unlock on error in sunxi_rsb_read()

Don't forget to unlock before returning an error code.

Fixes: d787dcdb ('bus: sunxi-rsb: Add driver for Allwinner Reduced Serial Bus')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

drivers/bus/sunxi-rsb.c

@@ -342,13 +342,13 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
 
 	ret = _sunxi_rsb_run_xfer(rsb);
 	if (ret)
-		goto out;
+		goto unlock;
 
 	*buf = readl(rsb->regs + RSB_DATA);
 
+unlock:
 	mutex_unlock(&rsb->lock);
 
-out:
 	return ret;
 }