[coreboot] patch: flashrom: add p680 motherboard, test AMIC A29040B, add EON EN29F040A, unify winbond W83697

[Alex Mauer]

Attached please find a patch for flashrom which does the following:
Adds support for the EON EN29F040A flash chip.
Marks the AMIC A29040B flash chip as tested.
Adds support for the Bcom WinNET P680 motherboard to flashrom.
Unifies flash-enable for the winbond W83697 superio.

Signed-off-by: Alex Mauer