timekeeping: Mark NMI safe time accessors as notrace

Mark the CLOCK_MONOTONIC fast time accessors as notrace. These functions are
used in tracing to retrieve timestamps, so they should not recurse.

Fixes: 4498e746 ("time: Parametrize all tk_fast_mono users")
Fixes: f09cb9a1

 ("time: Introduce tk_fast_raw")
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220426175338.3807ca4f@gandalf.local.home/
Link: https://lore.kernel.org/r/20220428062432.61063-1-kurt@linutronix.de