dyndbg: reverse module walk in cat control

/proc/dynamic_debug/control walks the prdbg catalog in "reverse",
fix this by adding new ddebug_tables to tail of list.

This puts init/main.c entries 1st, which looks more than coincidental.

no functional changes.
Acked-by: Jason Baron <jbaron@akamai.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Link: https://lore.kernel.org/r/20220904214134.408619-5-jim.cromie@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

lib/dynamic_debug.c

@@ -970,7 +970,7 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
 	dt->ddebugs = tab;
 
 	mutex_lock(&ddebug_lock);
-	list_add(&dt->link, &ddebug_tables);
+	list_add_tail(&dt->link, &ddebug_tables);
 	mutex_unlock(&ddebug_lock);
 
 	vpr_info("%3u debug prints in module %s\n", n, dt->mod_name);