ASoC: SOF: Fix potential NULL pointer dereference

Cleanup path for sof_prepare_widgets_in_path() should check if unprepare
callback exists before calling it, instead it checks if it does not
exist. Fix the check.

Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20220602135757.3335351-1-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/sof-audio.c

@@ -318,7 +318,7 @@ sink_prepare:
 			p->walking = false;
 			if (ret < 0) {
 				/* unprepare the source widget */
-				if (!widget_ops[widget->id].ipc_unprepare && swidget->prepared) {
+				if (widget_ops[widget->id].ipc_unprepare && swidget->prepared) {
 					widget_ops[widget->id].ipc_unprepare(swidget);
 					swidget->prepared = false;
 				}