coresight: adding comments to remove ambiguity

Add comment to function coresight_enable_path() to make
sure there is no misunderstanding about what the code does.
Signed-off-by: NMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight.c

@@ -240,6 +240,11 @@ static int coresight_enable_path(struct list_head *path)
 	int ret = 0;
 	struct coresight_device *cd;
 
+	/*
+	 * At this point we have a full @path, from source to sink.  The
+	 * sink is the first entry and the source the last one.  Go through
+	 * all the components and enable them one by one.
+	 */
 	list_for_each_entry(cd, path, path_link) {
 		if (cd == list_first_entry(path, struct coresight_device,
 					   path_link)) {