cavium: Return negative value when pci_alloc_irq_vectors() fails

During the process of driver probing, the probe function should return < 0
for failure, otherwise, the kernel will treat value > 0 as success.
Signed-off-by: NZheyu Ma <zheyuma97@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/cavium/thunder/nic_main.c

@@ -1193,7 +1193,7 @@ static int nic_register_interrupts(struct nicpf *nic)
 		dev_err(&nic->pdev->dev,
 			"Request for #%d msix vectors failed, returned %d\n",
 			   nic->num_vec, ret);
-		return 1;
+		return ret;
 	}
 
 	/* Register mailbox interrupt handler */