Parent SSI is needed if it is PIN sharing and clock master,
otherwise, not needed. But, whether clockk master is judged on
.set_fmt, thus, it can't call rsnd_ssi_parent_attach() on .probe.

Now, .pcm_new will be called after .set_fmt, so this patch reuses it
at this point.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>