bnxt_en: fix error return code in bnxt_init_board()

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

Fixes: c0c050c58d84 ("bnxt_en: New Broadcom ethernet driver.")
Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Zhang Changzhong <[e-mail]>
Reviewed-by: Edwin Peer <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

···
 	if (dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64)) != 0 &&
 	    dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)) != 0) {
 		dev_err(&pdev->dev, "System does not support DMA, aborting\n");
+		rc = -EIO;
 		goto init_err_disable;
 	}