[coreboot] [PATCH] v2: Enable -O2 / -mcpu=p2 for all 440BX romcc boards

[Uwe Hermann]

See patch.

Build-tested and tested on hardware using an ASUS P2B-F, I didn't notice
any problems. However, if there are any non-obvious reasons to _not_
enable optimizations in romcc, please let me know.

Uwe.