timers-core-2023-02-20

  Core:

    - Yet another round of improvements to make the clocksource watchdog
      more robust:

      	 - Relax the clocksource-watchdog skew criteria to match the NTP
           criteria.

	 - Temporarily skip the watchdog when high memory latencies are
	   detected which can lead to false-positives.

	 - Provide an option to enable TSC skew detection even on systems
           where TSC is marked as reliable.

      Sigh!

    - Initialize the restart block in the nanosleep syscalls to be directed
      to the no restart function instead of doing a partial setup on entry.

      This prevents an erroneous restart_syscall() invocation from
      corrupting user space data. While such a situation is clearly a user
      space bug, preventing this is a correctness issue and caters to the
      least suprise principle.

    - Ignore the hrtimer slack for realtime tasks in schedule_hrtimeout()
      to align it with the nanosleep semantics.

  Drivers:

    - The obligatory new driver bindings for Mediatek, Rockchip and RISC-V
      variants.

    - Add support for the C3STOP misfeature to the RISC-V timer to handle
      the case where the timer stops in deeper idle state.

    - Set up a static key in the RISC-V timer correctly before first use.

    - The usual small improvements and fixes all over the place