sched/rt: Add RT class changes snapshot

This snapshot is taken from msm-4.9 as of commit dd4275868d0fdb7
("sched/rt: Prevent leaking kernel address").

Change-Id: Ifb89c7549ef101ccb089c665b7e93b2c8130e849
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>