PM / devfreq: Remove the invalid description for get_target_freq

First of all, no_central_polling was removed since
commit 7e6fdd4bad ("PM / devfreq: Core updates to support devices
which can idle")
Secondly, get_target_freq() is not only called only with update_devfreq()
notified by OPP now, but also min/max freq qos notifier.

So remove this invalid description now to avoid confusing.

Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

Documentation/ABI/testing/sysfs-class-devfreq

@@ -97,10 +97,7 @@ Description:
 		object. The values are represented in ms. If the value is
 		less than 1 jiffy, it is considered to be 0, which means
 		no polling. This value is meaningless if the governor is
-		not polling; thus. If the governor is not using
-		devfreq-provided central polling
-		(/sys/class/devfreq/.../central_polling is 0), this value
-		may be useless.
+		not polling.
 
 		A list of governors that support the node:
 		- simple_ondmenad

drivers/devfreq/governor.h

@@ -57,8 +57,6 @@
  *			Basically, get_target_freq will run
  *			devfreq_dev_profile.get_dev_status() to get the
  *			status of the device (load = busy_time / total_time).
- *			If no_central_polling is set, this callback is called
- *			only with update_devfreq() notified by OPP.
  * @event_handler:      Callback for devfreq core framework to notify events
  *                      to governors. Events include per device governor
  *                      init and exit, opp changes out of devfreq, suspend