net: stmmac: dwmac-rk: fix error handling in rk_gmac_powerup()

If phy_power_on() fails in rk_gmac_powerup(), clocks are left enabled.

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

drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c

@@ -1342,8 +1342,10 @@ static int rk_gmac_powerup(struct rk_priv_data *bsp_priv)
 	}
 
 	ret = phy_power_on(bsp_priv, true);
-	if (ret)
+	if (ret) {
+		gmac_clk_enable(bsp_priv, false);
 		return ret;
+	}
 
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);