In this patch, all the vGPU type related code will be merged into
same gvt file and the common interface will be exposed to both
XenGT and KvmGT.

v2:
- remove the useless mdev_* gvt_ops.
  add get_gvt_attr ops for MPT module.
  intel_gvt_{init,cleanup}_vgpu_type_groups are initialized in
  gvt part. (Wang, Zhi)
- set gvt_vgpu_type_groups[i] to NULL. (Zhang,Xiong)
Signed-off-by: fred gao <fred.gao@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>