dm: core: Rename ofnode_get_property_by_prop()

The current name is quite unwieldy. Change it to use an ofprop_ prefix
and shorten it. Fix the return-value comment while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
index 2feca56..f9c9ca1 100644
--- a/drivers/core/ofnode.c
+++ b/drivers/core/ofnode.c
@@ -816,8 +816,8 @@
 	return 0;
 }
 
-const void *ofnode_get_property_by_prop(const struct ofprop *prop,
-					const char **propname, int *lenp)
+const void *ofprop_get_property(const struct ofprop *prop,
+				const char **propname, int *lenp)
 {
 	if (ofnode_is_np(prop->node))
 		return of_get_property_by_prop(ofnode_to_np(prop->node),