Fixed segmentation fault at server shutdown caused by r15521.

git-svn-id: https://svn.code.sf.net/p/rathena/svn/trunk@15522 54d463be-8e91-2dee-dedb-b68131a5f0ec

src/map/mob.c

@@ -4550,7 +4550,7 @@ int do_final_mob(void)
 			mob_chat_db[i] = NULL;
 		}
 	}
-	for (i = 0; i <= MAX_ITEMDB; i++)
+	for (i = 0; i < MAX_ITEMDB; i++)
 	{
 		if (item_drop_ratio_db[i] != NULL)
 		{