staging: brcm80211: remove kernel_thread() for _dhd_sysioc_thread.

Replaced kernel_thread() with kthread_run(), kthread_stop(), and
kthread_should_stop().  Also removed all references to sysioc_pid and
sysioc_exit.  DAEMONIZE removed because not used in dhd_linux.c.

sysioc_tsk is NULL when not running.

Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>