Cpufreq: create/remove percpu sysfs nodes once

On cpu hotplug on/off, percpu "cpufreq" sysfs node and it's
sub nodes are freshly created and removed. This increases
cpu up/down latency.

Create percpu "cpufreq" sysfs node and it's sub nodes in driver
registration and remove it in unregistration. This decreases
cpu up/down latency significantly.

Change-Id: I5c2b02e74de0ae4fe08dedc959bd7402cd9b7aa5
Signed-off-by: Puneet Saxena <puneets@nvidia.com>
Reviewed-on: http://git-master/r/146812
(cherry picked from commit 298382285677fa791098d117ccc0a0a3d9ab0f9a)
Reviewed-on: http://git-master/r/219379
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Sachin Nikam <snikam@nvidia.com>

modified for use on Mako by faux123

Signed-off-by: Paul Reioux <reioux@gmail.com>
nohz: stat: Fix CPU idle time accounting

Since cpustat[CPUTIME_IDLE] is never connected to ts->idle_sleeptime,
never read from cpustat[CPUTIME_IDLE] when reporting stats in
/proc/stat.

Note this was rejected by Michal Hocko when it was initially proposed
by Martin Schwidefsky in LKML, so if you want to upstream it, better
find an alternative (either completely disable cpustat[CPUTIME_IDLE]
for CONFIG_NO_HZ or somehow connect them to keep them in sync.)

bug 1190321

Change-Id: Idc92488910b826aff850a010016d8326c7ab9e6c
Signed-off-by: Bo Yan <byan@nvidia.com>
Reviewed-on: http://git-master/r/214638
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Liang Cheng (SW) <licheng@nvidia.com>
Tested-by: Liang Cheng (SW) <licheng@nvidia.com>
cpufreq: Resolve CPUFREQ_NOTIFY issue

When the cpufreq_stat receives the frequency policy notification,
it checks if the frequency table and stats table are present for the cpu.
If both are present, it returns with -EBUSY error to the notification.
Due to this, none of the other registered modules receive this
notification.

If the stat table and sysfs nodes are already created, return 0 instead
of returning EBUSY error.

Change-Id: I1fd4a46e6a65edfc6253c4271288f10912ae2ad7
Signed-off-by: Archana Sathyakumar <asathyak@codeaurora.org>