ANDROID: sched: Initial ksched_football test implementation

Reimplementation of the sched_football test from LTP:
https://github.com/linux-test-project/ltp/blob/master/testcases/realtime/func/sched_football/sched_football.c



But reworked to run in the kernel and utilize mutexes/rt_mutexes
to illustrate proper boosting of low priority mutex holders.

Cc: Joel Fernandes <joelaf@google.com>
Cc: Qais Yousef <qyousef@layalina.io>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Zimuzo Ezeozue <zezeozue@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Will Deacon <will@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Metin Kaya <Metin.Kaya@arm.com>
Cc: Xuewen Yan <xuewen.yan94@gmail.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: kernel-team@android.com
Change-Id: I26e5496c44bf3b1432e9d335b5509bd228b18f8e
Signed-off-by: John Stultz <jstultz@google.com>
Bug: 306081722
---
v8:
* Use rt_mutexes for !CONFIG_SCHED_PROXY_EXEC
* Bail if spawned players don't check in within 30s
* Numerous spelling corrections from Randy Dunlap and Metin Kaya
* Lots of other improvements suggested by Metin Kaya
* Minor checkpatch fixups
v9:
* A bunch more cleanups and improvements suggsted by Metin
* Use #defines for magic time and prio values, suggested by Metin
* Fail if CONFIG_SCHED_PROXY_EXEC=y but !sched_proxy_exec(), again
  pointed out by Metin
* Fix Kconfig entry to be bool instead of tristate as it doesn't
  really work as a module yet. Pointed out by Metin
* Few minor checkpatch fixups
v12:
* Renamed to ksched_football to avoid confusion with LTP test
* Enabled the test to be re-runnable via sysfs trigger
* Enabled the test to be run for longer periods of time via
  sysfs trigger