Merge branch 'upstream/ticketlock-cleanup' into upstream/xen

Merge branch 'upstream/ticketlock-cleanup' into upstream/xen

* upstream/ticketlock-cleanup:
  x86/ticketlock: make __ticket_spin_trylock common
  x86/ticketlock: convert __ticket_spin_lock to use xadd()
  x86/ticketlock: convert spin loop to C
  x86/ticketlock: clean up types and accessors
  x86: use xadd helper more widely
  x86: add xadd helper macro
  x86/cmpxchg: unify cmpxchg into cmpxchg.h
  x86/cmpxchg: move 64-bit set64_bit() to match 32-bit
  x86/cmpxchg: move 32-bit __cmpxchg_wrong_size to match 64 bit.
  x86/cmpxchg: linux/alternative.h has LOCK_PREFIX