[coreboot] coreboot.v2+seabios on 440bx: option roms not found

[Andriy Gapon]

In northbridge/intel/i440bx/raminit.c:sdram_set_spd_registers all PAM
registers are programmed for RAM R/W access (0x33).
When SeaBIOS searches for option ROMs (including VGA ROM) it doesn't do
anything about PAM, so it sees empty memory instead of the ROMs.

I am not sure what is the best solution here. It is debatable how
coreboot should set PAM register, and it is not right to make SeaBIOS
too hardware dependent.

Maybe coreboot could somehow export functions for setting access to
option ROM space (aka legacy memory segments) and SeaBIOS could call them.