ASOC: rockchip: fix capture stream handling in rockchip_sai_xfer_stop

Correcting the capture stream handling which was incorrectly setting
playback=true for capture streams.

The original code mistakenly set playback=true for capture streams,
causing incorrect behavior.

Fixes: cc78d1ea ("ASoC: rockchip: add Serial Audio Interface (SAI) driver")
Signed-off-by: Pei Xiao <xiaopei01@kylinos.cn>
Tested-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Acked-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://patch.msgid.link/c374aae92c177aaf42c0f1371eccdbc7e9615786.1749201126.git.xiaopei01@kylinos.cn


Signed-off-by: Mark Brown <broonie@kernel.org>