drivers: i2s: Support audio auxpll in TDM driver

Add support for audio_auxpll clock source as an alternative to audiopll
in the i2s_nrf_tdm driver. This enables TDM functionality on platforms
that use the auxiliary PLL for audio clocking.

- Add audio_auxpll node detection and configuration
- Update clock management to support both audiopll and audio_auxpll
- Add build assertions for supported frequency configurations

Signed-off-by: Erdem Simsek <erdem.simsek@nordicsemi.no>