ASoC: rsnd: enable/disable ADG when suspend/resume timing

Current rsnd driver enables ADG clock when .probe timing,
but it breaks sound after Suspend/Resume. These should be setups
every suspend/resume timing too.
This patch is tested on R-Car Gen3 Salvator-X board

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Tested-by: Gaku Inami <gaku.inami.xw@bp.renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>