drm/amdgpu: add cgs query info of pci bus devfn

Signed-off-by: Eric Huang <JinHuiEric.Huang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c
index e521920..383204e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c
@@ -875,6 +875,9 @@ static int amdgpu_cgs_query_system_info(struct cgs_device *cgs_device,
 	case CGS_SYSTEM_INFO_PCIE_SUB_SYS_VENDOR_ID:
 		sys_info->value = adev->pdev->subsystem_vendor;
 		break;
+	case CGS_SYSTEM_INFO_PCIE_BUS_DEVFN:
+		sys_info->value = adev->pdev->devfn;
+		break;
 	default:
 		return -ENODEV;
 	}