mlx4: remove unnecessary read of PCI_CAP_ID_EXP

The PCIE capability offset is saved during PCI bus walking.  It will
remove an unnecessary search in the PCI configuration space if this
value is referenced instead of reacquiring it.
Signed-off-by: NJon Mason <jdmason@kudzu.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/mlx4/reset.c

@@ -77,7 +77,7 @@ int mlx4_reset(struct mlx4_dev *dev)
 		goto out;
 	}
 
-	pcie_cap = pci_find_capability(dev->pdev, PCI_CAP_ID_EXP);
+	pcie_cap = pci_pcie_cap(dev->pdev);
 
 	for (i = 0; i < 64; ++i) {
 		if (i == 22 || i == 23)