Merge tag 'for-linus-20180922' of git://git.kernel.dk/linux-block

Jens writes:
  "Just a single fix in this pull request, fixing a regression in
  /proc/diskstats caused by the unification of timestamps."

* tag 'for-linus-20180922' of git://git.kernel.dk/linux-block:
  block: use nanosecond resolution for iostat