drm/i915/gvt: do not deliver a workload if its creation fails

in workload creation routine, if any failure occurs, do not queue this
workload for delivery. if this failure is fatal, enter into failsafe
mode.

Fixes: 6d763035 ("drm/i915/gvt: Move common vGPU workload creation into scheduler.c")
Cc: stable@vger.kernel.org #4.19+
Cc: zhenyuw@linux.intel.com
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

drivers/gpu/drm/i915/gvt/scheduler.c

@@ -1486,7 +1486,8 @@ intel_vgpu_create_workload(struct intel_vgpu *vgpu, int ring_id,
 		intel_runtime_pm_put_unchecked(dev_priv);
 	}
 
-	if (ret && (vgpu_is_vm_unhealthy(ret))) {
+	if (ret) {
+		if (vgpu_is_vm_unhealthy(ret))
 			enter_failsafe_mode(vgpu, GVT_FAILSAFE_GUEST_ERR);
 		intel_vgpu_destroy_workload(workload);
 		return ERR_PTR(ret);