[HACK] ipc4-mtrace: move read pointer with mtrace slot size all the time

this is wrong, but it looks like the user space wants this?

We will in essence tell user space that we have given 0x1000 of data all
the time while we never do that.
Oh well.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

sound/soc/sof/ipc4-mtrace.c

@@ -187,9 +187,9 @@ static ssize_t sof_ipc4_mtrace_read(struct file *file, char __user *buffer,
 	slot_data->host_read_ptr = write_ptr;
 
 	/* move debugfs reading position */
-	*ppos += avail;
+	*ppos += SOF_MTRACE_SLOT_SIZE;
 
-	return avail;
+	return SOF_MTRACE_SLOT_SIZE;
 }
 
 static const struct file_operations sof_dfs_mtrace_fops = {