x86-urgent-2020-06-11

  - Unbreak paravirt VDSO clocks. While the VDSO code was moved into lib
    for sharing a subtle check for the validity of paravirt clocks got
    replaced. While the replacement works perfectly fine for bare metal as
    the update of the VDSO clock mode is synchronous, it fails for paravirt
    clocks because the hypervisor can invalidate them asynchronous. Bring
    it back as an optional function so it does not inflict this on
    architectures which are free of PV damage.

  - Fix the jiffies to jiffies64 mapping on 64bit so it does not trigger
    an ODR violation on newer compilers

  - Three fixes for the SSBD and *IB* speculation mitigation maze to ensure
    consistency, not disabling of some *IB* variants wrongly and to prevent
    a rogue cross process shutdown of SSBD. All marked for stable.

  - Add yet more CPU models to the splitlock detection capable list !@#%$!

  - Bring the pr_info() back which tells that TSC deadline timer is enabled.

  - Reboot quirk for MacBook6,1