arm64:dts:tr8p: Clean-up SAI2, audio codec and simple-audio-card definition

- Remove duplicate of SAI2
- Revert the changes to the audio codec and simple-audio-card nodes

Note: The Trizeps VIII Plus v1r3 and newer has the WM8962 audio codec
equipped. For the overrides regarding this see the trizeps8plus_v1r3
include/override.