The LPC-Link is basically a JTAG/SWD debugger. I'm not sure, but with the LPC-link part attached it takes over control of the target part, meaning you have to program via the LPC-link.
If you carefully separate the LPC-link (I use an Xacto craft saw with a fine cut), then you have an LPC-link debugger and a target part. If you put a 10 pin header on your target board, you can then connect it to the LPC-link (or indeed any other JTAG/SWD debugger - I use Segger JLINK). Or you can connect via the 8way 0.1" header from LPC-link to your target board.
I guess that no-one has set up a Smoothieware with a JTAG debugger, but I think in principle there is no reason why it would not work, unless SMoothie uses the JTAG pins for something else?