drm/amdgpu: clean up discovery testing

Rather than checking of the variable is enabled and the
chip is the right family check for the presence of the
discovery table.

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Acked-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1533,7 +1533,7 @@ static int amdgpu_device_parse_gpu_info_fw(struct amdgpu_device *adev)
 
 	adev->firmware.gpu_info_fw = NULL;
 
-	if (amdgpu_discovery && adev->asic_type >= CHIP_NAVI10) {
+	if (adev->discovery_bin) {
 		amdgpu_discovery_get_gfx_info(adev);
 		return 0;
 	}
@@ -3374,7 +3374,7 @@ void amdgpu_device_fini(struct amdgpu_device *adev)
 	sysfs_remove_files(&adev->dev->kobj, amdgpu_dev_attributes);
 	if (IS_ENABLED(CONFIG_PERF_EVENTS))
 		amdgpu_pmu_fini(adev);
-	if (amdgpu_discovery && adev->asic_type >= CHIP_NAVI10)
+	if (adev->discovery_bin)
 		amdgpu_discovery_fini(adev);
 }