[CPUFREQ] update documentation

The sysfs directory where the cpufreq-related files are stored changed due
to the new device interface code, so the documentation needs to be updated
accordingly. Also, add some information about the reference counting and the
exporting of sysfs files by the drivers.

Documentation/cpu-freq/core.txt

@@ -35,6 +35,10 @@ speed limits (like LCD drivers on ARM architecture). Additionally, the
 kernel "constant" loops_per_jiffy is updated on frequency changes
 here.
 
+Reference counting is done by cpufreq_get_cpu and cpufreq_put_cpu,
+which make sure that the cpufreq processor driver is correctly
+registered with the core, and will not be unloaded until
+cpufreq_put_cpu is called.
 
 2. CPUFreq notifiers
 ====================

Documentation/cpu-freq/cpu-drivers.txt

@@ -63,6 +63,9 @@ And optionally
 
 cpufreq_driver.exit -		A pointer to a per-CPU cleanup function.
 
+cpufreq_driver.attr -		A pointer to a NULL-terminated list of
+				"struct freq_attr" which allow to
+				export values to sysfs.
 
 
 1.2 Per-CPU Initialization

Documentation/cpu-freq/user-guide.txt

@@ -114,9 +114,9 @@ the processor shall run at.
 ------------------------------
 
 The preferred interface is located in the sysfs filesystem. If you
-mounted it at /sys, the cpufreq interface is located in the 
-cpu-device directory (e.g. /sys/devices/sys/cpu0/ for the first
-CPU).
+mounted it at /sys, the cpufreq interface is located in a subdirectory
+"cpufreq" within the cpu-device directory
+(e.g. /sys/devices/sys/cpu0/cpufreq/ for the first CPU).
 
 cpuinfo_min_freq :		this file shows the minimum operating
 				frequency the processor can run at(in kHz) 
@@ -125,7 +125,7 @@ cpuinfo_max_freq :		this file shows the maximum operating
 scaling_driver :		this file shows what cpufreq driver is
 				used to set the frequency on this CPU
 
-available_scaling_governors :	this file shows the CPUfreq governors
+scaling_available_governors :	this file shows the CPUfreq governors
 				available in this kernel. You can see the
 				currently activated governor in