drm/i915/gvt: Refactor vGPU type code in kvmgt part

all the vGPU type related code in kvmgt will be moved into
gvt.c/gvt.h files while the common vGPU type related interfaces
will be called.

v2:
- intel_gvt_{init,cleanup}_vgpu_type_groups are initialized in
  gvt part. (Wang, Zhi)

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>