locking-core-2021-04-28

 - rtmutex cleanup & spring cleaning pass that removes ~400 lines of code
 - Futex simplifications & cleanups
 - Add debugging to the CSD code, to help track down a tenacious race (or hw problem)
 - Add lockdep_assert_not_held(), to allow code to require a lock to not be held,
   and propagate this into the ath10k driver
 - Misc LKMM documentation updates
 - Misc KCSAN updates: cleanups & documentation updates
 - Misc fixes and cleanups
 - Fix locktorture bugs with ww_mutexes

Signed-off-by: Ingo Molnar <mingo@kernel.org>