[coreboot] PMM support in SeaBIOS

[Kevin O'Connor]

The latest SeaBIOS git now supports Post Memory Manager (PMM) calls.
These calls are used by optionroms to allocate memory during bootup.

If anyone has had trouble with the execution of an optionrom, I
suggest retrying with the latest SeaBIOS git.  It's possible the
addition of PMM may improve execution.

Also, for those with working optionroms I suggest testing the latest
SeaBIOS git to verify there has been no regressions.

Finally, for further info on SeaBIOS with coreboot see:
http://www.coreboot.org/SeaBIOS

-Kevin