vfio: ccw: push down unsupported IDA check

There is at least one relevant guest OS that doesn't set the IDA flags in
the ORB as we would like them, but never uses any IDA. So instead of
saying -EOPNOTSUPP when observing an ORB, such that a channel program
specified by it could be a not supported one, let us say -EOPNOTSUPP only
if the channel program is a not supported one.

Of course, the real solution would be doing proper translation for all
IDA. This is possible, but given the current code not straight forward.

Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Tested-by: Jason J. Herne <jjherne@linux.ibm.com>
Message-Id: <20180516173342.15174-1-pasic@linux.ibm.com>
Reviewed-by: Dong Jia Shi <bjsdjshi@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>