myri10ge: fix error return code

Return a negative error code on failure.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
identifier ret; expression e1,e2;
@@
(
if (\(ret < 0\|ret != 0\))
 { ... return ret; }
|
ret = 0
)
... when != ret = e1
    when != &ret
*if(...)
{
  ... when != ret = e2
      when forall
 return ret;
}
// </smpl>

The patch also modifies the test of mgp->cmd to satisfy checkpatch.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/myricom/myri10ge/myri10ge.c

@@ -4033,8 +4033,10 @@ static int myri10ge_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	(void)pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
 	mgp->cmd = dma_alloc_coherent(&pdev->dev, sizeof(*mgp->cmd),
 				      &mgp->cmd_bus, GFP_KERNEL);
-	if (mgp->cmd == NULL)
+	if (!mgp->cmd) {
+		status = -ENOMEM;
 		goto abort_with_enabled;
+	}
 
 	mgp->board_span = pci_resource_len(pdev, 0);
 	mgp->iomem_base = pci_resource_start(pdev, 0);