Change in flashrom[staging]: Add a convenient libflashrom interface

[Nico Huber (Code Review)]

Nico Huber has posted comments on this change. ( https://review.coreboot.org/17946 )

Change subject: Add a convenient libflashrom interface
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Patch Set 9:

Will give this another iteration when we decided on the namespace prefix.
I have some ideas to refine some things yet, around flags and return
values. But I guess we should get this in first and make some amendments
later. I would consider the interface open for incompatible changes until
the next release.