forked from Mirrors/opensbi

We should skip baudrate config for UART8250 and SiFive UART when input frequency is zero. Signed-off-by: Anup Patel <anup.patel@wdc.com> Reviewed-by: Atish Patra <atish.patra@wdc.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>