renderer: check valid consts outside loop

This just moves a check outside the loop, as this is a bit of
a hotpath.

src/vrend_renderer.c

@@ -2789,11 +2789,11 @@ void vrend_draw_vbo(struct vrend_context *ctx,
    vrend_use_program(ctx, ctx->sub->prog->id);
 
    for (shader_type = PIPE_SHADER_VERTEX; shader_type <= ctx->sub->last_shader_idx; shader_type++) {
-      if (ctx->sub->prog->const_locs[shader_type] && (ctx->sub->const_dirty[shader_type] || new_program)) {
-         int nc;
-         nc = ctx->sub->shaders[shader_type]->sinfo.num_consts;
-         for (i = 0; i < nc; i++) {
-            if (ctx->sub->prog->const_locs[shader_type][i] != -1 && ctx->sub->consts[shader_type].consts)
+      if (ctx->sub->consts[shader_type].consts &&
+          ctx->sub->prog->const_locs[shader_type] &&
+          (ctx->sub->const_dirty[shader_type] || new_program)) {
+         for (i = 0; i < ctx->sub->shaders[shader_type]->sinfo.num_consts; i++) {
+            if (ctx->sub->prog->const_locs[shader_type][i] != -1)
                glUniform4uiv(ctx->sub->prog->const_locs[shader_type][i], 1, &ctx->sub->consts[shader_type].consts[i * 4]);
          }
          ctx->sub->const_dirty[shader_type] = false;