Pull RCU warning removal from Paul McKenney:
 "A single commit that fixes an embarrassing bug discussed here:

      https://lore.kernel.org/lkml/20200125131425.GB16136@zn.tnic/

  which apparently also affects smaller systems"

[ This was sent to Ingo, but since I see the issue on the laptop I use for
  testing during the merge window, I'm doing the pull directly     - Linus ]

* 'urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  rcu: Forgive slow expedited grace periods at boot time