stmmac: handle allocation errors in setup functions

If the allocations fail in either dwmac1000_setup() or dwmac100_setup()
then return NULL.  These are called from stmmac_mac_device_setup().  The
check for NULL returns in stmmac_mac_device_setup() needed to be moved
forward a couple lines.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/stmmac/dwmac1000_core.c

@@ -220,6 +220,8 @@ struct mac_device_info *dwmac1000_setup(unsigned long ioaddr)
 		((uid & 0x0000ff00) >> 8), (uid & 0x000000ff));
 
 	mac = kzalloc(sizeof(const struct mac_device_info), GFP_KERNEL);
+	if (!mac)
+		return NULL;
 
 	mac->mac = &dwmac1000_ops;
 	mac->dma = &dwmac1000_dma_ops;

drivers/net/stmmac/dwmac100_core.c

@@ -179,6 +179,8 @@ struct mac_device_info *dwmac100_setup(unsigned long ioaddr)
 	struct mac_device_info *mac;
 
 	mac = kzalloc(sizeof(const struct mac_device_info), GFP_KERNEL);
+	if (!mac)
+		return NULL;
 
 	pr_info("\tDWMAC100\n");
 

drivers/net/stmmac/stmmac_main.c

@@ -1558,15 +1558,15 @@ static int stmmac_mac_device_setup(struct net_device *dev)
 	else
 		device = dwmac100_setup(ioaddr);
 
+	if (!device)
+		return -ENOMEM;
+
 	if (priv->enh_desc) {
 		device->desc = &enh_desc_ops;
 		pr_info("\tEnhanced descriptor structure\n");
 	} else
 		device->desc = &ndesc_ops;
 
-	if (!device)
-		return -ENOMEM;
-
 	priv->hw = device;
 
 	priv->wolenabled = priv->hw->pmt;	/* PMT supported */