[S390] cio: fix double free after failed device initialization

If io_subchannel_initialize_dev fails it will release the only
reference to the ccw device therefore the caller should not
kfree this device since this is done in the release function.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>