Power ISA 2.07B section B.5.5 relaxed the barrier requirement around a
TLE enabled lock. It is now identical to a traditional lock.
2015-08-26 Paul E. Murphy <murphyp@linux.vnet.ibm.com>
* sysdeps/unix/sysv/linux/powerpc/elision-lock.c
(__arch_compare_and_exchange_val_32_acq): Remove and use common
definition. ISA 2.07B no longer requires full sync.