unicore32 i8042: adjust io funcs of i8042-unicore32io.h

replace inb/outb with readb/writeb in i8042-unicore32io.h
and correct typecasting of register and region macros
  -- by advice with Arnd Bergmann

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>