sched/rt: Prevent leaking kernel address

Use %pK instead of %p while printing the rt_rq in
dump_throttled_rt_tasks().

Change-Id: I5bfdbd458003b3a5b80394afc995a4d6f9e0ee0e
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>