All GVT supported platform has virtual display which should be
able to handle VFIO edid region. Enable this for all supported platform.

Cc: Hang Yuan <hang.yuan@linux.intel.com>
Cc: Fred Gao <fred.gao@intel.com>
Reviewed-by: Hang Yuan <hang.yuan@linux.intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20191202070109.73924-3-zhenyuw@linux.intel.com