net: stmmac: Fix unused values warnings

The commit 8532f613 ("net: stmmac: introduce MSI Interrupt routines
for mac, safety, RX & TX") introduced the converity warnings:-

  1. Unused value (UNUSED_VALUE)
     assigned_value: Assigning value REQ_IRQ_ERR_MAC to irq_err here,
     but that stored value is not used.

  2. Unused value (UNUSED_VALUE)
     assigned_value: Assigning value REQ_IRQ_ERR_NO to irq_err here,
     but that stored value is overwritten before it can used.

  3. Unused value (UNUSED_VALUE)
     assigned_value: Assigning value REQ_IRQ_ERR_WOL to irq_err here,
     but that stored value is not used.

Fixed these by removing the unnecessary value assignments.

Fixes: 8532f613 ("net: stmmac: introduce MSI Interrupt routines for mac, safety, RX & TX")
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -3406,8 +3406,8 @@ static void stmmac_free_irq(struct net_device *dev,
 
 static int stmmac_request_irq_multi_msi(struct net_device *dev)
 {
-	enum request_irq_err irq_err = REQ_IRQ_ERR_NO;
 	struct stmmac_priv *priv = netdev_priv(dev);
+	enum request_irq_err irq_err;
 	cpumask_t cpu_mask;
 	int irq_idx = 0;
 	char *int_name;
@@ -3554,8 +3554,8 @@ static int stmmac_request_irq_multi_msi(struct net_device *dev)
 
 static int stmmac_request_irq_single(struct net_device *dev)
 {
-	enum request_irq_err irq_err = REQ_IRQ_ERR_NO;
 	struct stmmac_priv *priv = netdev_priv(dev);
+	enum request_irq_err irq_err;
 	int ret;
 
 	ret = request_irq(dev->irq, stmmac_interrupt,
@@ -3565,7 +3565,7 @@ static int stmmac_request_irq_single(struct net_device *dev)
 			   "%s: ERROR: allocating the IRQ %d (error: %d)\n",
 			   __func__, dev->irq, ret);
 		irq_err = REQ_IRQ_ERR_MAC;
-		return ret;
+		goto irq_error;
 	}
 
 	/* Request the Wake IRQ in case of another line
@@ -3579,7 +3579,7 @@ static int stmmac_request_irq_single(struct net_device *dev)
 				   "%s: ERROR: allocating the WoL IRQ %d (%d)\n",
 				   __func__, priv->wol_irq, ret);
 			irq_err = REQ_IRQ_ERR_WOL;
-			return ret;
+			goto irq_error;
 		}
 	}