clocksource: Fix comments on WATCHDOG_THRESHOLD & WATCHDOG_MAX_SKEW

The WATCHDOG_THRESHOLD macro is no longer used to supply a default value
for ->uncertainty_margin, but WATCHDOG_MAX_SKEW now is.

Therefore, update the comments to reflect this change.

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/20240802154618.4149953-3-paulmck@kernel.org

Author: paulmckrcu

kernel/time/clocksource.c

@@ -113,7 +113,6 @@ static u64 suspend_start;
 
 /*
  * Threshold: 0.0312s, when doubled: 0.0625s.
- * Also a default for cs->uncertainty_margin when registering clocks.
  */
 #define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 5)
 
@@ -139,6 +138,13 @@ static u64 suspend_start;
 #define MAX_SKEW_USEC	(125 * WATCHDOG_INTERVAL / HZ)
 #endif
 
+/*
+ * Default for maximum permissible skew when cs->uncertainty_margin is
+ * not specified, and the lower bound even when cs->uncertainty_margin
+ * is specified.  This is also the default that is used when registering
+ * clocks with unspecifed cs->uncertainty_margin, so this macro is used
+ * even in CONFIG_CLOCKSOURCE_WATCHDOG=n kernels.
+ */
 #define WATCHDOG_MAX_SKEW (MAX_SKEW_USEC * NSEC_PER_USEC)
 
 #ifdef CONFIG_CLOCKSOURCE_WATCHDOG