[RFC] FPGA: add a simple framework for firmware programming

[Juergen Beisert]

This is just a simple API to be used within C programs or via a shell command
to be able to program firmware into an attached FPGA. To hide the details how
to deal with the specific FPGA a handler register itself which does the real
work.
All users of this API just have to provide a handler identifier and the
firmware file.
As an example I added a firmware handler for an ALTERA FPGA connected via SPI
as its programming interface.

Comments are welcome.

Juergen