Fix const assignment/discard warnings in the ATM networking driver.

The lane2_assoc_ind() function needed its arguments changing to match changes
in the lane2_ops struct (patch 61c33e01
"atm: use const where reasonable").
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Chas Williams <chas@cmf.nrl.navy.mil>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>