sched/debug: Show WALT specific details in /proc/sched_debug

WALT specific details can be very handy while debugging any
issue on live target.

Change-Id: I26f323393fd0f8d7c193f38dcea1531976d28272
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>