[coreboot] [PATCH] Eliminate some warnings treated as errors

[xdrudis]

After I copied mainboard/amd/tilapia-fam10 dir for mainboard/asus/m4a77td-pro,
adapted it a litlle
and changed mainboard/asus/Kconfig and makemenuconfig, I had 
to change a few small things because I got warnings treated as
erroes for unused symbols.

patch.warnerror

With only this patch applied to svn rev 5701 
I can compile but I can't see anything in the serial port.

(I can send the current diff between m4a77td-pro and tilapia-fam10, but maybe
I wait until it boots?)

Signed off by: Xavi Drudis Ferran