Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu

Pull percpu patch from Tejun Heo:
 "A puny pull request for percpu.  We were expecting more cleanup
  patches but didn't happen this time, so just a single patch adding
  documentation from Christoph."

* 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: add documentation on this_cpu operations