net: sun4i-emac: fix error return code

Return a negative error code on failure.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret; expression e1,e2;
@@
(
if (\(ret < 0\|ret != 0\))
 { ... return ret; }
|
ret = 0
)
... when != ret = e1
    when != &ret
*if(...)
{
  ... when != ret = e2
      when forall
 return ret;
}
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/allwinner/sun4i-emac.c

@@ -850,8 +850,10 @@ static int emac_probe(struct platform_device *pdev)
 	}
 
 	db->clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(db->clk))
+	if (IS_ERR(db->clk)) {
+		ret = PTR_ERR(db->clk);
 		goto out;
+	}
 
 	clk_prepare_enable(db->clk);