ASoC: sh: rz-ssi: Add full duplex support

Add full duplex support, to support simultaneous
playback/record on the same ssi channel.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20240715092322.119879-1-biju.das.jz@bp.renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>