ASoC: renesas: rz-ssi: Fix playback and capture

ASoC: renesas: rz-ssi: Fix playback and capture

In the current codebase the rz_ssi_stream_get() is called at the beginning
of rz_ssi_dai_trigger() before rz_ssi_stream_init() is called.
Since rz_ssi_stream_init() sets the ssi->{playback, capture}->substream,
relying on it in rz_ssi_stream_get() is incorrect. Fix this by checking
substream->stream instead as the original code did.

Fixes: 53dfb2ad6fcf ("ASoC: renesas: rz-ssi: Simplify the logic in rz_ssi_stream_is_play()")
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://patch.msgid.link/20260213172434.3801015-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>