iwlwifi: 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: Jon Mason <jdmason@kudzu.us>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-pci.c

@@ -94,7 +94,7 @@ static u16 iwl_pciexp_link_ctrl(struct iwl_bus *bus)
 	u16 pci_lnk_ctl;
 	struct pci_dev *pci_dev = IWL_BUS_GET_PCI_DEV(bus);
 
-	pos = pci_find_capability(pci_dev, PCI_CAP_ID_EXP);
+	pos = pci_pcie_cap(pci_dev);
 	pci_read_config_word(pci_dev, pos + PCI_EXP_LNKCTL, &pci_lnk_ctl);
 	return pci_lnk_ctl;
 }