[coreboot] PIC instead of APIC mode for KolibriOS - mouse fix

[Rudolf Marek]

Hi all,

1) we should provide at least the MP-Table. There is a still lot of OS without 
ACPI support (various homebrew OS, RTOS etc) which don't want to carry the 
ACPICA just to get idea how to route IRQs...

2) if we want to setup the PCI for PIC we need to do:

a) setup the PCI router (just couple of regs in the SB)
This is done by: pirq_assign_irqs()
b) setup the ELCR (0x4d0/0x4d1) set IRQs to level, this is done by: 
i8259_configure_irq_trigger()
c) setup the 0x3c values in the PCI regs this is done by: pirq_route_irqs() 
which does the job if CONFIG_PIRQ_ROUTE

Oh yes coreboot knows how to do that if PIR table is present in quite generic 
way. Setting this up should not break things, except that AMD SB700 or similar 
needs to disable the IRQ routing to PIC in ASL code in _PIC method. I don't know 
if this necessary.

Thanks
Rudolf