drm/i915/gvt: fix unhandled mmio warnings

some registers were missing or treated as BDW only. This patch is to fix it
avoid unhandled mmio wanrings

v2: update commit message according to zhenyu's comment

Signed-off-by: Zhao Yan <yan.y.zhao@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
1 file changed