avutil/log: Reorder elements of AVClass to make it smaller

Putting child_next besides child_class_iterate is actually nicer.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavutil/log.h

@@ -106,11 +106,6 @@ typedef struct AVClass {
      */
     int parent_log_context_offset;
 
-    /**
-     * Return next AVOptions-enabled child or NULL
-     */
-    void* (*child_next)(void *obj, void *prev);
-
     /**
      * Category used for visualization (like color)
      * This is only set if the category is equal for all objects using this class.
@@ -130,6 +125,11 @@ typedef struct AVClass {
      */
     int (*query_ranges)(struct AVOptionRanges **, void *obj, const char *key, int flags);
 
+    /**
+     * Return next AVOptions-enabled child or NULL
+     */
+    void* (*child_next)(void *obj, void *prev);
+
     /**
      * Iterate over the AVClasses corresponding to potential AVOptions-enabled
      * children.