ANDROID: Export sysctl_sched_wakeup_granularity to enable modifying it

The value is only available in debugfs. Export it to allow out of tree
modules to modify it.

Bug: 340857074
Bug: 337139487
Signed-off-by: Qais Yousef <qyousef@google.com>
Change-Id: I4b3a5aeeee0539b88756aacc97df6181f68d9d0d
(cherry picked from commit 0d080e01)