[coreboot] LegacyBIOS -> SeaBIOS in buildrom

[Myles Watson]

> This patch changes the name of LegacyBIOS to SeaBIOS, everywhere but the
> git
> URL, which hasn't been updated yet.  It also updates the hardcode.diff
> patch
> now that the memory value is read from the coreboot tables, and fixes the
> handling of that patch.
> 
> Thanks,
> Myles
> 
> Signed-off-by: Myles Watson <mylesgw at gmail.com>

I forgot to say that I used svn mv for the name changes, so it looks bigger
than it was.

Thanks,
Myles