x86: qemu: move x86 specific operations out of qfw core

The original implementation of qfw includes several x86 specific
operations, like directly calling outb/inb and using some inline
assembly code which prevents it being ported to other architectures.

This patch adds callback functions and moves those to arch/x86/

Signed-off-by: Miao Yan <yanmiaobest@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>