drm/i915/gvt: clear ggtt entries when destroy vgpu

When one vgpu is destroyed, its ggtt entries are not cleared.
This patch clears ggtt entries to avoid information leak.

v2: add 'Fixes' tag (Zhenyu)

Fixes: 2707e4446688 ("drm/i915/gvt: vGPU graphics memory virtualization")
Signed-off-by: Zhipeng Gong <zhipeng.gong@intel.com>
Reviewed-by: Hang Yuan <hang.yuan@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

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

@@ -281,6 +281,7 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)
 	intel_vgpu_clean_submission(vgpu);
 	intel_vgpu_clean_display(vgpu);
 	intel_vgpu_clean_opregion(vgpu);
+	intel_vgpu_reset_ggtt(vgpu, true);
 	intel_vgpu_clean_gtt(vgpu);
 	intel_gvt_hypervisor_detach_vgpu(vgpu);
 	intel_vgpu_free_resource(vgpu);