When a siox master device is registered a kthread is created that is
only started when triggered by userspace. So this thread might be in
TASK_UNINTERRUPTIBLE state for long and trigger a warning
[ 241.130465] INFO: task siox-0:626 blocked for more than 120 seconds.
with the respective debug settings enabled. It might be right to put an
unstarted thread to TASK_IDLE (in kernel/kthread.c:kthread()) instead,
but independant of this discussion it is cleaner for
siox_master_register() to start the thread immediately. The effect is
that it enters its own waiting state and then stays in state TASK_IDLE
which doesn't trigger the above warning.
As siox_poll_thread() uses some variables of the device the
initialisation of these is moved before thread creation.