clocksource: Improve comments for watchdog skew bounds

Add more detail on the rationale for bounding the clocksource
->uncertainty_margin below at about 500ppm.

Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: John Stultz <jstultz@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: Feng Tang <feng.tang@intel.com>
1 file changed