ASoC: rsnd: adg: tidyup rsnd_adg_get_clkin/out() parameter

set priv->adg before rsnd_adg_get_clkin/out() to be more simple code.
Nothing is changed, but is preparation for
next "ASoC: rsnd: adg: use more simple method for null_clk" patch

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87sg21i21j.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>