ASoC: xilinx: formatter_pcm: fix stream_data leak on open error

ASoC: xilinx: formatter_pcm: fix stream_data leak on open error

In xlnx_formatter_pcm_open(), stream_data is allocated and
adata->play_stream or adata->capture_stream is assigned early.  If a
later step, such as snd_pcm_hw_constraint_step() or
snd_pcm_hw_constraint_integer(), fails, the function returns the error
immediately.  ALSA does not call the close callback when open fails, so
stream_data is leaked and the stream pointer is left dangling, pointing
to a substream that ALSA frees.  A later interrupt would then call
snd_pcm_period_elapsed() on the freed substream.

Free stream_data and clear the stream pointer on the error paths.

Fixes: 6f6c3c36f091 ("ASoC: xlnx: add pcm formatter platform driver")
Assisted-by: opencode:deepseek-v4-flash-free
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Reviewed-by: Michal Simek <michal.simek@amd.com>
Link: https://patch.msgid.link/20260811185140.27149-1-rosenp@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>