ASoC: SDCA: Add missing default in switch in entity_pde_event()

The current code should be safe as the PDE widget only registers for the
two events handled in the switch statement. However, it is causing a
smatch warning and also is a little fragile to future code changes, add
a default case to avoid the warning and make the code more robust.

Fixes: 2c8b3a8 ("ASoC: SDCA: Create DAPM widgets and routes from DisCo")
Reported-by: Dan Carpenter <[email protected]>
Reviewed-by: Bard Liao <[email protected]>
Signed-off-by: Charles Keepax <[email protected]>
Reviewed-by: Pierre-Louis Bossart <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: charleskeepax

sound/soc/sdca/sdca_asoc.c

@@ -397,6 +397,8 @@ static int entity_pde_event(struct snd_soc_dapm_widget *widget,
 		from = widget->off_val;
 		to = widget->on_val;
 		break;
+	default:
+		return 0;
 	}
 
 	for (i = 0; i < entity->pde.num_max_delay; i++) {