ASoC: Intel: avs: Clearly state assumptions of hw_params()

There are no NULL-checks for fe/be_hw_params as there is an implicit
assumption that framework opens valid DPCMs only. State that clearly.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://patch.msgid.link/20250109122216.3667847-9-cezary.rojewski@intel.com


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