ASoC: fsl-asoc-card: Allow passing the number of slots in use

Currently, fsl-asoc-card supports passing the width of the TDM slot, but
not the number of slots in use, as it harcodes it as two slots.

Add support for passing the number of slots in use.
Signed-off-by: Fabio Estevam <festevam@denx.de>
Link: https://lore.kernel.org/r/20230616203913.551183-1-festevam@gmail.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl-asoc-card.c

@@ -62,6 +62,7 @@ struct codec_priv {
  * @sysclk_dir: SYSCLK directions for set_sysclk()
  * @sysclk_id: SYSCLK ids for set_sysclk()
  * @slot_width: Slot width of each frame
+ * @slot_num: Number of slots of each frame
  *
  * Note: [1] for tx and [0] for rx
  */
@@ -70,6 +71,7 @@ struct cpu_priv {
 	u32 sysclk_dir[2];
 	u32 sysclk_id[2];
 	u32 slot_width;
+	u32 slot_num;
 };
 
 /**
@@ -191,7 +193,11 @@ static int fsl_asoc_card_hw_params(struct snd_pcm_substream *substream,
 	}
 
 	if (cpu_priv->slot_width) {
-		ret = snd_soc_dai_set_tdm_slot(asoc_rtd_to_cpu(rtd, 0), 0x3, 0x3, 2,
+		if (!cpu_priv->slot_num)
+			cpu_priv->slot_num = 2;
+
+		ret = snd_soc_dai_set_tdm_slot(asoc_rtd_to_cpu(rtd, 0), 0x3, 0x3,
+					       cpu_priv->slot_num,
 					       cpu_priv->slot_width);
 		if (ret && ret != -ENOTSUPP) {
 			dev_err(dev, "failed to set TDM slot for cpu dai\n");