net: ethernet: lantiq_etop: fix build errors/warnings

Fix build error and warnings reported by kernel test robot:

drivers/net/ethernet/lantiq_etop.c: In function 'ltq_etop_probe':
drivers/net/ethernet/lantiq_etop.c:673:15: error: implicit declaration of function 'device_property_read_u32' [-Werror=implicit-function-declaration]
     673 |         err = device_property_read_u32(&pdev->dev, "lantiq,tx-burst-length", &priv->tx_burst_len);

   drivers/net/ethernet/lantiq_etop.c: At top level:
   drivers/net/ethernet/lantiq_etop.c:730:1: warning: no previous prototype for 'init_ltq_etop' [-Wmissing-prototypes]
     730 | init_ltq_etop(void)

   drivers/net/ethernet/lantiq_etop.c: In function 'ltq_etop_hw_init':
   drivers/net/ethernet/lantiq_etop.c:276:25: warning: ignoring return value of 'request_irq' declared with attribute 'warn_unused_result' [-Wunused-result]
     276 |                         request_irq(irq, ltq_etop_dma_irq, 0, "etop_tx", priv);
   drivers/net/ethernet/lantiq_etop.c:284:25: warning: ignoring return value of 'request_irq' declared with attribute 'warn_unused_result' [-Wunused-result]
     284 |                         request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv);

Fixes: 14d4e30 ("net: lantiq: configure the burst length in ethernet drivers")
Fixes: dddb29e ("net: lantiq_etop: remove deprecated IRQF_DISABLED")
Fixes: 504d472 ("MIPS: Lantiq: Add ethernet driver")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Link: lore.kernel.org/r/202111090621.yjr9xuVj-lkp@intel.com
To: netdev@vger.kernel.org
Cc: Aleksander Jan Bajkowski <olek2@wp.pl>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: John Crispin <john@phrozen.org>
Cc: linux-mips@vger.kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/lantiq_etop.c

@@ -25,6 +25,7 @@
 #include <linux/io.h>
 #include <linux/dma-mapping.h>
 #include <linux/module.h>
+#include <linux/property.h>
 
 #include <asm/checksum.h>
 
@@ -239,6 +240,7 @@ ltq_etop_hw_init(struct net_device *dev)
 {
 	struct ltq_etop_priv *priv = netdev_priv(dev);
 	int i;
+	int err;
 
 	ltq_pmu_enable(PMU_PPE);
 
@@ -273,15 +275,27 @@ ltq_etop_hw_init(struct net_device *dev)
 
 		if (IS_TX(i)) {
 			ltq_dma_alloc_tx(&ch->dma);
-			request_irq(irq, ltq_etop_dma_irq, 0, "etop_tx", priv);
+			err = request_irq(irq, ltq_etop_dma_irq, 0, "etop_tx", priv);
+			if (err) {
+				netdev_err(dev,
+					   "Unable to get Tx DMA IRQ %d\n",
+					   irq);
+				return err;
+			}
 		} else if (IS_RX(i)) {
 			ltq_dma_alloc_rx(&ch->dma);
 			for (ch->dma.desc = 0; ch->dma.desc < LTQ_DESC_NUM;
 					ch->dma.desc++)
 				if (ltq_etop_alloc_skb(ch))
 					return -ENOMEM;
 			ch->dma.desc = 0;
-			request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv);
+			err = request_irq(irq, ltq_etop_dma_irq, 0, "etop_rx", priv);
+			if (err) {
+				netdev_err(dev,
+					   "Unable to get Rx DMA IRQ %d\n",
+					   irq);
+				return err;
+			}
 		}
 		ch->dma.irq = irq;
 	}
@@ -726,7 +740,7 @@ static struct platform_driver ltq_mii_driver = {
 	},
 };
 
-int __init
+static int __init
 init_ltq_etop(void)
 {
 	int ret = platform_driver_probe(&ltq_mii_driver, ltq_etop_probe);