drm/i915/gvt: not to restore in-context mmio

Needn't to restore the in-context MMIO when SCHEDULE_OUT. Sometimes
with restoring the in-context MMIO, some GPU hang can be observed. So
remove the in-context MMIO restore

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

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

@@ -333,6 +333,9 @@ void intel_gvt_restore_render_mmio(struct intel_vgpu *vgpu, int ring_id)
 		} else
 			v = mmio->value;
 
+		if (mmio->in_context)
+			continue;
+
 		I915_WRITE(mmio->reg, v);
 		POSTING_READ(mmio->reg);