Hi joeschlupf,
What’s your Jetpack version in use?
Do you mean that you have the similar design for your custom carrier board as the devkit and you want to use the default BSP package for your custom board?
You can refer to How to enable TPM2.0 module in Xavier? - Jetson & Embedded Systems / Jetson AGX Xavier - NVIDIA Developer Forums to port the TPM module but we would suggest you asking the porting guide from your vendor.
You can select any unused GPIO as interrupt in your case but it seems not needed for TPM.