audio: host-zephyr: clean DMA if channel set at free

Add code to check for a valid DMA channel in host_common_free()
and if a DMA channel is set, stop the channel and free DMA
resources.

Issue found in code review. This should not be hit in normal
use-cases, but this makes the free implementation more robust in
case of errors.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

src/audio/host-zephyr.c

@@ -784,6 +784,13 @@ __cold void host_common_free(struct host_data *hd)
 	}
 #endif
 
+	/* release DMA channel if not already done by reset */
+	if (hd->chan_index != -EINVAL) {
+		sof_dma_stop(hd->dma, hd->chan_index);
+		sof_dma_release_channel(hd->dma, hd->chan_index);
+		hd->chan_index = -EINVAL;
+	}
+
 	sof_dma_put(hd->dma);
 
 	ipc_msg_free(hd->msg);