intel_sst: make sure the sst_drop_stream() get called when needed

When "aplay test.wav", if we "ctrl+z" to suspend it, the last piece of
sound will be played endlessly. So we need make sure the drop_stream
is called in such a case.
Signed-off-by: NFeng Tang <feng.tang@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/intel_sst/intel_sst_drv_interface.c

@@ -283,8 +283,8 @@ void sst_process_mad_ops(struct work_struct *work)
 		retval = sst_resume_stream(mad_ops->stream_id);
 		break;
 	case SST_SND_DROP:
-/*		retval = sst_drop_stream(mad_ops->stream_id);
-*/		break;
+		retval = sst_drop_stream(mad_ops->stream_id);
+		break;
 	case SST_SND_START:
 			pr_debug("SST Debug: start stream\n");
 		retval = sst_start_stream(mad_ops->stream_id);