[coreboot] Flashrom patch

[Maciej Pijanka]

Hello

I tried vortex-diag on some 3com card and reading/writing flash was
working, so i tried to add it to nic3com.c (patch attached)

Also, i added AT29C512 Atmel flash chip to flashchips.c to get it
autodetected (patch also attached).

Final flashrom -p nic3com -V log is in patched-detection.log

best regards
Maciej Pijanka