ixgbe: use pcie_capability_read_word() to simplify code

use pcie_capability_read_word() to simplify code.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -153,7 +153,6 @@ MODULE_VERSION(DRV_VERSION);
 static int ixgbe_read_pci_cfg_word_parent(struct ixgbe_adapter *adapter,
 					  u32 reg, u16 *value)
 {
-	int pos = 0;
 	struct pci_dev *parent_dev;
 	struct pci_bus *parent_bus;
 
@@ -165,11 +164,10 @@ static int ixgbe_read_pci_cfg_word_parent(struct ixgbe_adapter *adapter,
 	if (!parent_dev)
 		return -1;
 
-	pos = pci_find_capability(parent_dev, PCI_CAP_ID_EXP);
-	if (!pos)
+	if (!pci_is_pcie(parent_dev))
 		return -1;
 
-	pci_read_config_word(parent_dev, pos + reg, value);
+	pcie_capability_read_word(parent_dev, reg, value);
 	return 0;
 }