nv30/draw: use ps instead of fn

Pushes an extra push if pn != 0.

Signed-off-by: Yusuf Khan <yusisamerican@gmail.com>

src/gallium/drivers/nouveau/nv30/nv30_draw.c

@@ -187,7 +187,7 @@ nv30_render_draw_arrays(struct vbuf_render *render, unsigned start, uint nr)
    PUSH_DATA (push, r->prim);
 
    BEGIN_NI04(push, NV30_3D(VB_VERTEX_BATCH), ps);
-   while (fn--) {
+   while (ps--) {
       PUSH_DATA (push, 0xff000000 | start);
       start += 256;
    }