net: bcmgenet: fix error returns in bcmgenet_probe()

The driver forgets to call clk_disable_unprepare() in error path after
a success calling for clk_prepare_enable().

Fix to goto err_clk_disable if clk_prepare_enable() is successful.

Fixes: 99d55638 ("net: bcmgenet: enable NETIF_F_HIGHDMA flag")
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Acked-by: Doug Berger <opendmb@gmail.com>
Acked-by: Florian fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmgenet.c

@@ -3988,7 +3988,7 @@ static int bcmgenet_probe(struct platform_device *pdev)
 	if (err)
 		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
 	if (err)
-		goto err;
+		goto err_clk_disable;
 
 	/* Mii wait queue */
 	init_waitqueue_head(&priv->wq);