ntb: clean up unnecessary MSI/MSI-X capability find

PCI core will initialize device MSI/MSI-X capability in
pci_msi_init_pci_dev(). So device driver should use
pci_dev->msi_cap/msix_cap to determine whether the device
support MSI/MSI-X instead of using
pci_find_capability(pci_dev, PCI_CAP_ID_MSI/MSIX).
Access to PCIe device config space again will consume more time.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Jon Mason <jon.mason@intel.com>

drivers/ntb/ntb_hw.c

@@ -1031,16 +1031,15 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 	struct pci_dev *pdev = ndev->pdev;
 	struct msix_entry *msix;
 	int msix_entries;
-	int rc, i, pos;
+	int rc, i;
 	u16 val;
 
-	pos = pci_find_capability(pdev, PCI_CAP_ID_MSIX);
-	if (!pos) {
+	if (!pdev->msix_cap) {
 		rc = -EIO;
 		goto err;
 	}
 
-	rc = pci_read_config_word(pdev, pos + PCI_MSIX_FLAGS, &val);
+	rc = pci_read_config_word(pdev, pdev->msix_cap + PCI_MSIX_FLAGS, &val);
 	if (rc)
 		goto err;