ASoC: SOF: amd: Fix NULL pointer crash in acp_sof_ipc_msg_data function

Check substream and runtime variables before assigning.

Signed-off-by: V sujith kumar Reddy <Vsujithkumar.Reddy@amd.com
Link: https://lore.kernel.org/r/20230508070510.6100-1-Vsujithkumar.Reddy@amd.com
Signed-off-by: Mark Brown <broonie@kernel.org

sound/soc/sof/amd/acp-ipc.c

@@ -209,7 +209,12 @@ int acp_sof_ipc_msg_data(struct snd_sof_dev *sdev, struct snd_sof_pcm_stream *sp
 		acp_mailbox_read(sdev, offset, p, sz);
 	} else {
 		struct snd_pcm_substream *substream = sps->substream;
-		struct acp_dsp_stream *stream = substream->runtime->private_data;
+		struct acp_dsp_stream *stream;
+
+		if (!substream || !substream->runtime)
+			return -ESTRPIPE;
+
+		stream = substream->runtime->private_data;
 
 		if (!stream)
 			return -ESTRPIPE;