UPSTREAM: sched/debug: Add new tracepoint to track cpu_capacity

rq->cpu_capacity is a key element in several scheduler parts, such as EAS
task placement and load balancing. Tracking this value enables testing
and/or debugging by a toolkit.

Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
(cherry picked from 51cf18c9)
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1598605249-72651-1-git-send-email-vincent.donnefort@arm.com



Bug: 171956327
Change-Id: I6f734e3240c4b6b904202b0af99f2e9b89dfcbd2
Signed-off-by: Jimmy Shiu <jimmyshiu@google.com>