mesa: fix shininess check for ffvertex_prog v2

Switch to using VERT_BIT_GENERIC macro, as varying_vp_inputs is a
bitmask.

Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Cc: mesa-stable@lists.freedesktop.org

src/mesa/main/ffvertex_prog.c

@@ -135,7 +135,7 @@ static GLboolean check_active_shininess( struct gl_context *ctx,
        (key->light_color_material_mask & (1 << attr)))
       return GL_TRUE;
 
-   if (key->varying_vp_inputs & VERT_ATTRIB_GENERIC(attr))
+   if (key->varying_vp_inputs & VERT_BIT_GENERIC(attr))
       return GL_TRUE;
 
    if (ctx->Light.Material.Attrib[attr][0] != 0.0F)