[coreboot] ACPI support on M57SLI

[Myles Watson]

I don't have the hardware, so I can't test.

+unsigned long write_acpi_tables(unsigned long start)
+{
+	get_bus_conf();
+	sbdn = sysconf.sbdn;

Since sbdn isn't used in write_acpi_tables, could you make it a local
variable in acpi_fill_madt instead and move that code there?
write_acpi_tables is pretty generic, and will eventually be factored out at
least per northbridge, so it makes sense to keep it as clean as possible. 

fadt.c should be in the southbridge/nvidia/mcp55/ directory.  Won't it work
for any board that has that chipset?

In Config.lb it seems like the indenting isn't uniform.  Could you use tabs
to make it cleaner?  Also in dsdt.asl there are multiple lines that have
indented blank lines.

Thanks,
Myles