[LinuxBIOS] [RFC] Multiple payload support in v3

[Alex Beregszaszi]

Hi,

attached is the multiple payload support originally by Uwe Hermann. I am
lazy to attach Uwe's Kconfig and Makefile changes, get them at:
http://www.linuxbios.org/pipermail/linuxbios/2007-August/023728.html

To be less obtrusive, created a run_payload function which does the
logic already present. This function will be called in every iteration
(normal/payload0..9 and as a last resolt normal/payload).

Added pusha/popa around payload entry points. Not a big safety otoh.

In no means is this mature enough for a commit.