Add support for more than one Super I/O or EC per machine.
flashrom currently only supports exactly one Super I/O or Embedded
Controller, and this means quite a few notebooks and a small subset of
desktop/server boards cannot be handled reliably and easily.
Allow detection and initialization of up to 3 Super I/O and/or EC chips.
WARNING! If a Super I/O or EC responds on multiple ports (0x2e and
0x4e), the code will do the wrong thing (namely, initialize the hardware
twice). I have no idea if we should handle such situations, and whether
we should ignore the second chip with identical ID or not. Initializing
the hardware twice for the IT87* family is _not_ a problem, but I don't
know how well IT85* can handle it (and whether IT85* would listen at
more than one port anyway).