[PATCH v6] Add optimized Makefile support for SoCFPGA handoff

[Sune Brian]

> Yes, it really needs to not be in the top level Makefile, the more stuff
> we have there the trickier upstream merges get, especially when this can
> be hooked to archprepare and work just fine. Thanks.

Done~ see v7

Now back to the documentation you want.
Where and what should be included.
If possible, a good example can help me settle things faster.

Brian