'share-rw' for the disk device configures qemu to allow concurrent
access to the backing storage.
The capability is checked in various supported disk frontend buses since
it does not make sense to partially backport it.
Add a separate capability for the sclplmconsole device, and check it
specifically instead of using QEMU_CAPS_DEVICE_SCLPCONSOLE for that too.
Signed-off-by: Pino Toscano <ptoscano@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>