bonding: Relax unneeded _safe lists iterations.

Many places either do not modify the list under the list_for_each_xxx,
or break out of the loop as soon as the first element is removed.

Thus, this _safe iteration just occupies some unneeded .text space
and requires an additional variable.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>