iucv: fix build error on !SMP

iucv: fix build error on !SMP

Since a5fbb6d1064be885d2a6b82f625186753cf74848
"KVM: fix !SMP build error" smp_call_function isn't a define anymore
that folds into nothing but a define that calls up_smp_call_function
with all parameters. Hence we cannot #ifdef out the unused code
anymore...
This seems to be the preferred method, so do this for s390 as well.

net/iucv/iucv.c: In function 'iucv_cleanup_queue':
net/iucv/iucv.c:657: error: '__iucv_cleanup_queue' undeclared

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Josef 'Jeff' Sipek <jeffpc@josefsipek.net>
Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>