When I try to create a project for the CC2538, my device is not available in the dropdown menu. How can I install support for this? I already have the CC2538 Foundation Firmware downloaded and have even followed the steps in the bsp users guide to manually include the libraries needed for a project. However, I still can't create a proper target configuration since I don't have support for that device. Is there a repository I need to install from in the Install New Software menu?