rmixl_com_init_regs
static void rmixl_com_init_regs(struct com_regs *, bus_space_tag_t,
rmixl_com_init_regs(®s, bst, ioh, addr);
rmixl_com_init_regs(&sc->sc_regs, bst, ioh, addr);
rmixl_com_init_regs(®s, bst, 0, addr);