net: mv643xx_eth: disable clk on error path in mv643xx_eth_shared_probe()

If mv643xx_eth_shared_of_probe() fails, mv643xx_eth_shared_probe()
leaves clk enabled.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mv643xx_eth.c

@@ -2879,7 +2879,7 @@ static int mv643xx_eth_shared_probe(struct platform_device *pdev)
 
 	ret = mv643xx_eth_shared_of_probe(pdev);
 	if (ret)
-		return ret;
+		goto err_put_clk;
 	pd = dev_get_platdata(&pdev->dev);
 
 	msp->tx_csum_limit = (pd != NULL && pd->tx_csum_limit) ?
@@ -2887,6 +2887,11 @@ static int mv643xx_eth_shared_probe(struct platform_device *pdev)
 	infer_hw_params(msp);
 
 	return 0;
+
+err_put_clk:
+	if (!IS_ERR(msp->clk))
+		clk_disable_unprepare(msp->clk);
+	return ret;
 }
 
 static int mv643xx_eth_shared_remove(struct platform_device *pdev)