How to modify pin assignments and generate device tree files based on CC6UL or CC8X?

Please use smart IOmux tool to configure and generate the device tree files.
Download IOmux  tool from the below link.
https://ftp1.digi.com/support/smartiomux/index.html
 
IOmux  tool  help doc is at the below link.
https://www.digi.com/resources/documentation/digidocs/90001937