ASoC: loongson: Remove useless variable definitions

In the function loongson_pcm_trigger and loongson_pcm_open,
the 'ret' is useless, so remove it to simplify code.

Signed-off-by: tangbin <tangbin@cmss.chinamobile.com>
Link: https://patch.msgid.link/20240713153428.44858-1-tangbin@cmss.chinamobile.com


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