s390/iucv: do not use arrays as argument

The iucv code uses arrays as arguments. Even though this does not
really cause a problem, it could be misleading, since the compiler
turns array arguments into just a pointer argument. To be more
precise this patch changes the array arguments into pointers.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>