imxuart_init
int imxuart_init(struct imxuart_regs *, int, tcflag_t, int);
res = imxuart_init(®s, rate, cflag, true);
res = imxuart_init(&imxu_kgdb_regs, rate, cflag, true);
imxuart_init(&sc->sc_regs, TTYDEF_SPEED, TTYDEF_CFLAG, false);
imxuart_init(0, UART1_BASE);
imxuart_init(0, bh);