regulators: Remove monitoring freq from comments

Update doxygen comments to remove the exact frequency of sensor
monitoring and phase fault detection.

Currently sensors are monitored every second and phase faults are
detected every 15 seconds.  However, that could change in the future.

Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
Change-Id: I3ac39955721fde98dfe9e6059693ceeea7e504c2
diff --git a/phosphor-regulators/src/chassis.hpp b/phosphor-regulators/src/chassis.hpp
index b0f8561..dc86ed0 100644
--- a/phosphor-regulators/src/chassis.hpp
+++ b/phosphor-regulators/src/chassis.hpp
@@ -122,7 +122,7 @@
     /**
      * Detect redundant phase faults in regulator devices in this chassis.
      *
-     * This method should be called every 15 seconds.
+     * This method should be called repeatedly based on a timer.
      *
      * @param services system services like error logging and the journal
      * @param system system that contains this chassis
@@ -166,7 +166,7 @@
      * Monitors the sensors for the voltage rails produced by this chassis, if
      * any.
      *
-     * This method should be called once per second.
+     * This method should be called repeatedly based on a timer.
      *
      * @param services system services like error logging and the journal
      * @param system system that contains the chassis