cpufreq: cpu-boost: Fix deadlock in wake_up of sync threads

If wake_up() is called on the current task on a CPU, the call will wait
until the current task is switched out before it wakes it up again and
returns.

The sync notifier for a CPU always runs on that CPU.

These two together can result in a deadlock if the sync notifier on CPU A
tries to wake up the sync thread of CPU A as it goes to sleep (is the
current task). A previous commit fixed this by adding a check to the sync
notifier to not wake up the sync thread of CPU A if it's the current task.

But this is still not sufficient to prevent deadlocks.

Sync thread of CPU A could be the current task on CPU B and sync thread of
CPU B could be the current task on CPU A.  At this point, if sync notifier
of CPU A and B try to wake up the sync threads of CPU A and B, it will
result in CPU A waiting for the current task in CPU B to get switched out
and CPU B waiting for the current task in CPU A to get switched out.  This
will result in a deadlock.

Prevent this scenario from happening by pinning the sync threads of each
CPU to run on that CPU. By doing this, we guarantee that sync notifiers
will only try to wake up sync threads running on that CPU. The fix added by
"cpufreq: cpu-boost: Resolve deadlock when waking up sync thread" ensures a
deadlock doesn't happen when a sync notifier tries to wake up a sync thread
running on that CPU.

Change-Id: I864e545529722a23886dd5a82f66089155d2d193
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
cpufreq: ondemand: Remove unnecessary synchronization attempt

Commit 1ce28d6b (ondemand: updated tune for hardware coordination)
brings in an attempt to synchronize expiry of per-cpu ondemand timer
at same time across all online cpus. This is meant to help systems
where "multiple cores share P-state via Hardware Coordination".

Synchronization is achieved by having timers expire when jiffy value
would be a perfect multiple of sampling window size. While such
synchronozation attemps are unnecessary on systems where cores don't
share P-states, it can hurt on power as cpus can now work off shorter
sampling windows (when percentage utilization over short window can be
observed to be high, causing frequency to be boosted).

Remove this unnecessary attempt to synchronize expiry of ondemand
timer across online cpus. A more acceptable solution could be to have
low-level architecture specific cpufreq driver indicate the need for
synchronization.

Change-Id: I6cb1cf3472ca106f029dc01248e0df7cfbb495b8
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>