[coreboot] Qemu fixes

[Myles Watson]

This patch adds high table support to qemu.  It was already added to
src/northbridge/intel/i440bx/ but not to
src/cpu/emulation/qemu-x86/northbridge.c

It also adds a driver for the ISA device that is found when using
0.9.1  If you look in a log without this patch you won't find the RTC
init lines.

The (un)fortunate thing is that it works (boots) either way.  Maybe
this will fix some PIRQ problems that were really because the table
was being overwritten by SeaBIOS.

Signed-off-by: Myles Watson

Thanks,
Myles