net: bcm4908: Handle dma_set_coherent_mask error codes

The return value of dma_set_coherent_mask() is not always 0.
To catch the exception in case that dma is not support the mask.

Fixes: 9d61d138 ("net: broadcom: rename BCM4908 driver & update DT binding")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bcm4908_enet.c

@@ -708,7 +708,9 @@ static int bcm4908_enet_probe(struct platform_device *pdev)
 
 	enet->irq_tx = platform_get_irq_byname(pdev, "tx");
 
-	dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
+	err = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
+	if (err)
+		return err;
 
 	err = bcm4908_enet_dma_alloc(enet);
 	if (err)