ASoC: rsnd: Add ADG reset support for RZ/G3E

ASoC: rsnd: Add ADG reset support for RZ/G3E

RZ/G3E requires the ADG reset line to be deasserted for the audio
subsystem to operate. The ADG module clock is already managed via
rsnd_adg_clk_enable/disable() through adg->adg, so no additional
clock handling is needed.

Add support for the optional "adg" reset control on Renesas RZ/G3E SoC.

Signed-off-by: John Madieu <john.madieu.xa@bp.renesas.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://patch.msgid.link/20260525110230.4014435-13-john.madieu.xa@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>