[PATCH 3.16.y-ckt 110/185] ARC: add smp barriers around atomics per Documentation/atomic_ops.txt

3.16.7-ckt15 -stable review patch. If anyone has any objections, please let me know. -- From: Vineet Gupta commit 2576c28e3f623ed401db7e6197241865328620ef upstream. - arch_spin_lock/unlock were lacking the ACQUIRE/RELEASE barriers Since ARCv2 only provides load/load,

[PATCH 3.16.y-ckt 110/185] ARC: add smp barriers around atomics per Documentation/atomic_ops.txt

3.16.7-ckt15 -stable review patch. If anyone has any objections, please let me know. -- From: Vineet Gupta vgu...@synopsys.com commit 2576c28e3f623ed401db7e6197241865328620ef upstream. - arch_spin_lock/unlock were lacking the ACQUIRE/RELEASE barriers Since ARCv2 only