2.6.38 added WARN_ON(in_irq) in del_timer_sync that triggers on zd1211rw when
reseting rx idle timer in urb completion handler.

Move timer reseting to tasklet.
Signed-off-by: NJussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>