s390/netiucv: get rid of one memcpy in netiucv_printuser

Save a memcpy in netiucv_printuser().

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>