hrtimer: update timer->state with 'pinned' information

'Pinned' information would be required in migrate_hrtimers() now, as we can
migrate non-pinned timers away without a hotplug (i.e. with cpuset.quiesce). And
so we may need to identify pinned timers now, as we can't migrate them.

This patch reuses the timer->state variable for setting this flag as there were
enough number of free bits available in this variable. And there is no point
increasing size of this struct by adding another field.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[forward port to 3.18]
Signed-off-by: Santosh Shukla <santosh.shukla@linaro.org>
[ohaugan@codeaurora.org: Port to 4.4]
Git-commit: 62feaf1ed0b64c04868d143d8bdb92d60dc3189b
Git-repo: git://git.linaro.org/people/mike.holmes/santosh.shukla/lng-isol.git


Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
[markivx: Port to 4.14, fix merge conflicts due to lack of timer stats code]
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>

Change-Id: Id2cdd74903598e31fab6999c4cbab9c2fd17fe23
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>