This change allows other device types to derive from common flashrom
code in the flashrom-device type.
Change-Id: Ic963fd586e0a73153c54889fce50055753a1bf5c
The coreboot plugin never actually gained the ability to write. As it stands a
coreboot system now adds *two* system-firmware devices (from both flashrom and
coreboot) which isn't ideal.
Just allow flashrom to enumerate quirked devices and add coreboot-specific
metadata as required. If we require some kind of cbfs parsing then we can do
that in FuFlashromDevice->prepare_firmware().
