Add ULX4M-LS and ULX4M-LD FPGA Boards

[gojimmypi]

Check out the ULX4M coming soon to Crowd Supply to add to the list of CM4 Carriers

[gojimmypi]

I've updated #536 to reflect there are actually two different ULX4M boards: the LX4M-LD (DDR3) and ULX4M-LS (SDRAM) flavors