On most x86 boards, the legacy serial ports (io address 0x3f8/0x2f8)
are provided by a superio chip connected to the LPC bus. We must
program the superio chip so that serial ports are available for us.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
