tracing: Introduce trace clock tai

A fast/NMI safe accessor for CLOCK_TAI has been introduced.
Use it for adding the additional trace clock "tai".

Link: https://lkml.kernel.org/r/20220414091805.89667-3-kurt@linutronix.de



Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>