sched: Make task load information available in /proc

The scheduler maintains load information for every non-realtime task.
This represents how cpu bound a task is. Expose this information in
/proc for debug purposes.

Change-Id: If0ad8ab896b8a0deaa6391ec295b503d60d74dc6
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>