drm/amdgpu: Fix NULL pointer when ta is missing

Ta is optional, so check if ta firmware is loaded or not.
Signed-off-by: xinhui pan <xinhui.pan@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -707,10 +707,13 @@ static int psp_hw_start(struct psp_context *psp)
 				"XGMI: Failed to initialize XGMI session\n");
 	}
 
+
+	if (psp->adev->psp.ta_fw) {
 		ret = psp_ras_initialize(psp);
 		if (ret)
 			dev_err(psp->adev->dev,
 					"RAS: Failed to initialize RAS\n");
+	}
 
 	return 0;
 }
@@ -963,6 +966,7 @@ static int psp_hw_fini(void *handle)
 	    psp->xgmi_context.initialized == 1)
                 psp_xgmi_terminate(psp);
 
+	if (psp->adev->psp.ta_fw)
 		psp_ras_terminate(psp);
 
 	psp_ring_destroy(psp, PSP_RING_TYPE__KM);
@@ -998,11 +1002,13 @@ static int psp_suspend(void *handle)
 		}
 	}
 
+	if (psp->adev->psp.ta_fw) {
 		ret = psp_ras_terminate(psp);
 		if (ret) {
 			DRM_ERROR("Failed to terminate ras ta\n");
 			return ret;
 		}
+	}
 
 	ret = psp_ring_stop(psp, PSP_RING_TYPE__KM);
 	if (ret) {