[coreboot] option rom new progress

[Jason Wang]

Hi all
    Since a few days passed, the option rom have already got some new
progress.
1)  the size have already expanded to 127.5K
2) the rom can been run not only in segment 0xce00, all of the hardcode
things have already been removed.
3) the init and int13 have already been improved within some details.

my next progress is going to make the option rom init funciton can detect
the usb devices