Add Lattice MachXO3LF Starter Kit

[trabucayre]

Hello,
This is the board definition for the Lattice MachX03LF Starter Kit.
Successfully tested with the blinky example.

Regards,
Gwenhael Goavec-Merou

[whitequark]

Thanks for the PR; looks reasonable to me. There's one minor issue though; are you sure that using the MachXO2 platform is appropriate?

[trabucayre]

I'm agree, it's seems a bit strange but all my tests with this platform and my machXO3 based board works well...
In fact, before sending this PR, I have hesitated due to this "detail".
Of course maybe I'm wrong but...

[whitequark]

Okay, I checked and all of the primitives match between MachXO2 and MachXO3L, so we should rename the platform to something like vendor.lattice_machxo_2_3l.

[trabucayre]

True. It's maybe less error prone.
Would you like I do it? with this name?

[whitequark]

Would you like I do it? with this name?

Yes. Please look at how it's done for Xilinx, and do the same for MachXO.

[whitequark]

Thanks!