gallium: replace loop w/ memset in draw_vertex_cache_invalidate()

src/mesa/pipe/draw/draw_vertex_cache.c

@@ -37,19 +37,11 @@
 
 void draw_vertex_cache_invalidate( struct draw_context *draw )
 {
-   unsigned i;
-
    assert(draw->pq.queue_nr == 0);
    assert(draw->vs.queue_nr == 0);
    assert(draw->vcache.referenced == 0);
-   /* XXX memset() here */
-#if 0
-   for (i = 0; i < Elements( draw->vcache.idx ); i++)
-      draw->vcache.idx[i] = ~0;
-#else
+
    memset(draw->vcache.idx, ~0, sizeof(draw->vcache.idx));
-#endif
-//   fprintf(stderr, "x\n");
 }