drm/radeon: Use PCI Express Capability accessors

Use PCI Express Capability access functions to simplify radeon driver.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/evergreen.c

@@ -77,13 +77,9 @@ void evergreen_tiling_fields(unsigned tiling_flags, unsigned *bankw,
 void evergreen_fix_pci_max_read_req_size(struct radeon_device *rdev)
 {
 	u16 ctl, v;
-	int cap, err;
+	int err;
 
-	cap = pci_pcie_cap(rdev->pdev);
-	if (!cap)
-		return;
-
-	err = pci_read_config_word(rdev->pdev, cap + PCI_EXP_DEVCTL, &ctl);
+	err = pcie_capability_read_word(rdev->pdev, PCI_EXP_DEVCTL, &ctl);
 	if (err)
 		return;
 
@@ -95,7 +91,7 @@ void evergreen_fix_pci_max_read_req_size(struct radeon_device *rdev)
 	if ((v == 0) || (v == 6) || (v == 7)) {
 		ctl &= ~PCI_EXP_DEVCTL_READRQ;
 		ctl |= (2 << 12);
-		pci_write_config_word(rdev->pdev, cap + PCI_EXP_DEVCTL, ctl);
+		pcie_capability_write_word(rdev->pdev, PCI_EXP_DEVCTL, ctl);
 	}
 }