BACKPORT: sched: Add a new function to compare if two cpus have the same capacity

The new helper function is needed to help blk-mq check if it needs to
dispatch the softirq on another CPU to match the performance level the
IO requester is running at. This is important on HMP systems where not
all CPUs have the same compute capacity.

Bug: 341551538
Change-Id: I58f3f3e3560f4800b5c73b3c85bbfdf628e9764e
Signed-off-by: Qais Yousef <qyousef@layalina.io>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240223155749.2958009-2-qyousef@layalina.io


Signed-off-by: Jens Axboe <axboe@kernel.dk>
(cherry picked from commit b361c902)
[Trivial clash due to code shuffling between the versions]
Signed-off-by: Qais Yousef <qyousef@google.com>