audio: return Error ** from audio_state_by_name

Remove duplicate error formatting code.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

ui/dbus.c

@@ -220,9 +220,8 @@ dbus_display_complete(UserCreatable *uc, Error **errp)
     }
 
     if (dd->audiodev && *dd->audiodev) {
-        AudioState *audio_state = audio_state_by_name(dd->audiodev);
+        AudioState *audio_state = audio_state_by_name(dd->audiodev, errp);
         if (!audio_state) {
-            error_setg(errp, "Audiodev '%s' not found", dd->audiodev);
             return;
         }
         if (!g_str_equal(audio_state->drv->name, "dbus")) {