atl1: fix resume

adapter->cmb.cmb is initialized when the device is opened and freed when
it's closed. Accessing it unconditionally during resume results either
in a crash (NULL pointer dereference, when the interface has not been
opened yet) or data corruption (when the interface has been used and
brought down adapter->cmb.cmb points to a deallocated memory area).

Cc: stable@kernel.org
Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Acked-by: Chris Snook <chris.snook@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>