Revert "sched: reduce sleep duration in wait_task_inactive()"

Upstream commit '26c7295be0c5e("kthread: Do not preempt current
task if it is going to call schedule()")' makes parent thread to not
call wait_task_inactive(child) on kthread create completion, which
intern avoids calling schedule_hrtimeout() and reduce bootup latencies.

The commit 'a9e87164(sched: reduce sleep duration in
wait_task_inactive())' reduces wait time to 1msec to avoid bootup
latencies. Which can be reverted now.

Change-Id: I4b2fd0abe5a264f4d662bdeab4160d1977ef6c22
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>