Staging: batman-adv: initialize static hash iterators

instead of dynamically registering hash iterators, calling functions are
changed to register the iterator objects statically. The two advantages are:

 * no memory leaks when aborting from hash_iterate()
 * no calls to kmalloc/kfree, therefore a little faster/safer

Tested with 9 QEMU instances, no obvious regression found.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>