tests: virtio: separate ccw tests from libqos

tests: virtio: separate ccw tests from libqos

Because qtest does not support s390 channel I/O, s390 only performs smoke tests on
those few devices that do not have any functional tests.  Therefore, every time we
add functional tests for a virtio device, the choice is between removing
those tests from the s390 suite (so that s390 actually _loses_ coverage)
or sprinkling the test with architecture checks.

This patch simply creates a ccw-specific test that only performs smoke tests on
all virtio-ccw devices.  If channel I/O support is ever added to qtest and libqos,
then this file can go away.  In the meanwhile, it simplifies maintenance and
makes sure that all virtio devices are tested.

Acked-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>