net: b44: fix error return code in b44_init_one()

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 39a6f4b ("b44: replace the ssb_dma API with the generic DMA API")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://lore.kernel.org/r/1605582131-36735-1-git-send-email-zhangchangzhong@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Zhang Changzhong

drivers/net/ethernet/broadcom/b44.c

@@ -2383,7 +2383,8 @@ static int b44_init_one(struct ssb_device *sdev,
 		goto err_out_free_dev;
 	}
 
-	if (dma_set_mask_and_coherent(sdev->dma_dev, DMA_BIT_MASK(30))) {
+	err = dma_set_mask_and_coherent(sdev->dma_dev, DMA_BIT_MASK(30));
+	if (err) {
 		dev_err(sdev->dev,
 			"Required 30BIT DMA mask unsupported by the system\n");
 		goto err_out_powerdown;