Replace daemonize() routine with daemone() system call, because of
conflicting licenses. daemonize() routine was derived from under
GNU Free Documentation License licensed code. This license is
incompatible with GPL-2+.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>