audio: Free consumed default audio devices

Failed default audio devices were removed from the list but not freed,
and that made LeakSanitizer sad. Free default audio devices as they are
consumed.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20231120112804.9736-1-akihiko.odaki@daynix.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>