This patch implements arch-specific ps2 driver.

By reviewed with Dmitry Torokhov:
     1. move i8042-ucio.h to drivers/input/serio/i8042-unicore32io.h
     2. move puv3_ps2_init() to arch/unicore32/kernel/puv3-core.c
     3. remove unused comments.
Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Dmitry Torokhov <dtor@mail.ru>