ASoC: SOF: ipc4-topology: Fix use of unitialized value

Initialize ref_params to zero in order to fix static analyzer
error:

ipc4-topology.c: In function ‘sof_ipc4_prepare_copier_module’:
ipc4-topology.c:1810:34: error: use of uninitialized value
‘((int *)<unknown>)[2]’ [CWE-457] [-Werror=analyzer-use-of-uninitialized-value]
struct snd_pcm_hw_params ref_params;

Note that this is a false positive, as manually inspecting the code there
is no path where ref_params is used unitialized.

Fixes: f920964 ("ASoC: SOF: ipc4-topology: Correct DAI copier config and NHLT blob request")
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>

sound/soc/sof/ipc4-topology.c

@@ -1807,7 +1807,7 @@ sof_ipc4_prepare_copier_module(struct snd_sof_widget *swidget,
 	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
 	struct sof_ipc4_copier_data *copier_data;
 	int input_fmt_index, output_fmt_index;
-	struct snd_pcm_hw_params ref_params;
+	struct snd_pcm_hw_params ref_params = { 0 };
 	struct sof_ipc4_copier *ipc4_copier;
 	struct snd_sof_dai *dai;
 	u32 gtw_cfg_config_length;