baords: bl5340_dvk: Add MCP4725 dac to bl5340_dvk_cpuapp dts file

MCP4725 is an I2C dac that was added with PR #33481. This can now be
added to the bl5340_dvk device tree.

Signed-off-by: Kieran Mackey <kieran.mackey@lairdconnect.com>