hw: better i440 emulation

hw: better i440 emulation

updated version of an old patch
http://xenon.stanford.edu/~eswierk/misc/qemu-linuxbios/qemu-piix-ram-size.patch
that together with
http://www.mail-archive.com/linuxbios@linuxbios.org/msg02390.html
(which is already in coreboot trunk) allows coreboot to autodetect the amount of RAM within qemu/kvm from a register in i440 northbridge.

The message on the old patch states:
Unfortunately the current version of qemu does not set these
registers, but I have patched qemu so that it emulates the i440 more
faithfully in this regard.

Signed-off-by: Bernhard M. Wiedemann <qemudevbmw@lsmod.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>