add ip-less option for non intel/xilinx

This is the same implementation used in v1.1
but with added ip-less ddr io.

Hopefully it covers lattice and others but I don't know
enough about those to confirm.

Xilinx support on master branch (#20)

xilinx oserdese2 + 4k30fps

proper support for DDR on Xilinx

Confirm platform support for Xilinx

Update discussion on DDC I2C