There is no I2C expander present on the G65D development kit. Please connect with iWave for the system.dts file, which supports all the interfaces available on the G65D devkit.
The clock synthesizer are not configured in the DTSI file. Instead, they are configured in the FSBL source code. For detailed information regarding clock configuration, please refer to Clock Synthesizer from the Software User Manual.
For further inquiries, please get in touch with mktg@iwave-global.com
Please find the detailed G65D product information in the below link,
https://iwave-global.com/product/zynq-ultrascale-zu15-zu9-zu6-system-on-module/