ASoC: Intel: avs: Remove dead code

The result of list_next_entry()/list_last_entry() is never null.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://msgid.link/r/20240405090929.1184068-10-cezary.rojewski@intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>