s390x/event-facility: fix receive mask check

For selective read event, we need to check if any event is requested
that is not active instead of whether none of the requested events is
active.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Eric Farman <farman@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>