netiucv: get rid of in_atomic() use

There is no urgent need to restart a netiucv connection automatically,
if packets are sent while the netiucv device is not up and running.

Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>