[coreboot] Gigabyte M57SLI-S4 Interrupt Fix

[Harald Gutmann]

Hello,

after a few tries of me to fix the interrupt problems which occurred on the 
M57SLI here is the final patch from me.

The Patch fixes the following issues on M57SLI:
* Interrupt routing in the MPTable

which affects the following hardware parts:
* PCI-E 16x Slots (blue and black) - both are working now like a charm
* PCI-E 1x Slots - all three should be fine, but I have no card to test. 
(untested)
* PCI Slots - both work fine now.

This is the first and (hopefully) the last patch on this issue which gets a

Signed-off-by: Harald Gutmann

from me.

I'm really looking forward to commit this patch (which is my first one) and 
mark the interrupt issues on the wiki page to the M57SLI as solved. :)

Kind regards,
Harald Gutmann