sched: fair: Improve sched_task_util trace point

Currently, sched_task_util trace point does not print final target cpu
selected for task placement.

Add the support to easy trace analysis.

Change-Id: I0a953a68ac9021de35619085fdc55d7ef802d7d0
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>