of: Migrate of_find_node_by_name() users to for_each_node_by_name()

There are a bunch of users open coding the for_each_node_by_name() by
calling of_find_node_by_name() directly instead of using the macro. This
is getting in the way of some cleanups, and the possibility of removing
of_find_node_by_name() entirely. Clean it up so that all the users are
consistent.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/ppc/pmac.c b/sound/ppc/pmac.c
index 7a43c0c..8a431bc 100644
--- a/sound/ppc/pmac.c
+++ b/sound/ppc/pmac.c
@@ -992,9 +992,9 @@
 		return -ENODEV;
 
 	if (!sound) {
-		sound = of_find_node_by_name(NULL, "sound");
-		while (sound && sound->parent != chip->node)
-			sound = of_find_node_by_name(sound, "sound");
+		for_each_node_by_name(sound, "sound")
+			if (sound->parent == chip->node)
+				break;
 	}
 	if (! sound) {
 		of_node_put(chip->node);