sh_eth: exit probe with unknown register layout

Exit the driver's probe() method when the register layout is unknown as the
driver would cause kernel oops in this case anyway.

While at it, move the corresponding error message printout and convert it from
pr_err() to dev_err().
Suggested-by: NJoe Perches <joe@perches.com>
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/sh_eth.c

@@ -2703,7 +2703,6 @@ static const u16 *sh_eth_get_register_offset(int register_type)
 		reg_offset = sh_eth_offset_fast_sh3_sh2;
 		break;
 	default:
-		pr_err("Unknown register type (%d)\n", register_type);
 		break;
 	}
 
@@ -2859,6 +2858,12 @@ static int sh_eth_drv_probe(struct platform_device *pdev)
 		mdp->cd = (struct sh_eth_cpu_data *)match->data;
 	}
 	mdp->reg_offset = sh_eth_get_register_offset(mdp->cd->register_type);
+	if (!mdp->reg_offset) {
+		dev_err(&pdev->dev, "Unknown register type (%d)\n",
+			mdp->cd->register_type);
+		ret = -EINVAL;
+		goto out_release;
+	}
 	sh_eth_set_default_cpu_data(mdp->cd);
 
 	/* set function */