bcmstb_decompose_tag
static void bcmstb_decompose_tag(void *, pcitag_t, int *, int *, int *);
pc->pc_decompose_tag = bcmstb_decompose_tag;
bcmstb_decompose_tag(v, tag, &bus, &dev, &fn);
bcmstb_decompose_tag(v, tag, &bus, &dev, &fn);