ISE patches are cumulative, so patch 8 includes all the previous fixes in the previous patches, log4j patch is among them. Also, if you look at Cisco software portal, you will see the latest hotfix you can find for kog4j only available for ISE 3.1 patch 1. From patch 3 on, the log4j hotfix has been already added to the patches themselves, so no need to apply any separate hotfix for it, you should be able to check that by looking at the resolved caveats in patch 8 release notes.
Release Notes for Cisco Identity Services Engine, Release 3.1 - Cisco
