nvc0: enable ARB_tessellation_shader on GM107+

This exposes OpenGL 4.1 on Maxwell (tested on GM107 and GM206).

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/gallium/drivers/nouveau/nvc0/nvc0_screen.c

@@ -308,11 +308,8 @@ nvc0_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
    case PIPE_SHADER_GEOMETRY:
    case PIPE_SHADER_FRAGMENT:
    case PIPE_SHADER_COMPUTE:
-      break;
    case PIPE_SHADER_TESS_CTRL:
    case PIPE_SHADER_TESS_EVAL:
-      if (class_3d >= GM107_3D_CLASS)
-         return 0;
       break;
    default:
       return 0;