In the worst case, ath9k_rng_stop() may take 10s to stop rng kthread.
The time is too long for users, use wait_event_interruptible_timeout()
instead of msleep_interruptible(), wakup immediately once
kthread_should_stop() is true.
Signed-off-by: NMiaoqing Pan <miaoqing@codeaurora.org>
Signed-off-by: NKalle Valo <kvalo@qca.qualcomm.com>