d3d12: Enable base instance and draw params extensions

Reviewed-by: Sil Vilerino <sivileri@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14486>

src/gallium/drivers/d3d12/d3d12_screen.cpp

@@ -304,6 +304,10 @@ d3d12_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
          return D3D12_UAV_SLOT_COUNT;
       return 0;
 
+   case PIPE_CAP_START_INSTANCE:
+   case PIPE_CAP_DRAW_PARAMETERS:
+      return 1;
+
    default:
       return u_pipe_screen_get_param_defaults(pscreen, param);
    }