isdn/eicon: don't call flush_scheduled_work() from diva_os_remove_soft_isr()
diva doesn't use workqueue and there is no reason to flush the system
workqueue from diva_os_remove_soft_isr(). Remove it.
This is to prepare for the deprecation and removal of
flush_scheduled_work().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Armin Schindler <armin@melware.de>