trace/events/sched: print the affinity in task_util

Currently affinity is only printed in enq_deq traces. Print it in
task_util traces to aid debugging of sched placement decisions.

Change-Id: If915102652e1ae666d4dd0136951839666c45243
Signed-off-by: Sai Harshini Nimmala <snimmala@codeaurora.org>