ASoC: Intel: avs: Allow to specify custom configurations with i2s_test

ASoC: Intel: avs: Allow to specify custom configurations with i2s_test

Change 'i2s_test' module option from enable-flag to string allowing to
specify which SSP port and in what TDM configuration should be enabled.

Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://patch.msgid.link/20250404090337.3564117-6-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>