It looks like this is two of the three needed files. I'm still missing the imx8dxl-evk.cfg file that should go in the ftdi directory.
I think I have the second config file in this command, but not the first config file:
openocd -f tcl/interface/ftdi/imx8dxl-evk.cfg -f tcl/board/imx8dxl-evk.cfg