drm/amdgpu: simplify ATPX detection

Use the base class rather than the specific class and drop
the second loop.
Reviewed-by: NEvan Quan <evan.quan@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c

@@ -613,17 +613,7 @@ static bool amdgpu_atpx_detect(void)
 	bool d3_supported = false;
 	struct pci_dev *parent_pdev;
 
-	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
-		vga_count++;
-
-		has_atpx |= (amdgpu_atpx_pci_probe_handle(pdev) == true);
-
-		parent_pdev = pci_upstream_bridge(pdev);
-		d3_supported |= parent_pdev && parent_pdev->bridge_d3;
-		amdgpu_atpx_get_quirks(pdev);
-	}
-
-	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_OTHER << 8, pdev)) != NULL) {
+	while ((pdev = pci_get_class(PCI_BASE_CLASS_DISPLAY << 16, pdev)) != NULL) {
 		vga_count++;
 
 		has_atpx |= (amdgpu_atpx_pci_probe_handle(pdev) == true);