nv50: do not advertise about compute shaders

Compute shaders are totally unsupported. This avoids Clover to
report that OpenCL is supported on Tesla because it's a lie.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Pierre Moreau <pierre.morrow@free.fr>
Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/gallium/drivers/nouveau/nv50/nv50_screen.c

@@ -264,8 +264,8 @@ nv50_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
    case PIPE_SHADER_VERTEX:
    case PIPE_SHADER_GEOMETRY:
    case PIPE_SHADER_FRAGMENT:
-   case PIPE_SHADER_COMPUTE:
       break;
+   case PIPE_SHADER_COMPUTE:
    default:
       return 0;
    }