intel_media: update qos requests instead of add/remove

commit 5b127e3b introduced accesses to pm_qos requests in workqueues
and hence some race conditions leading sometimes to kernel panics.
To be thread-safe, initialize the request once and for all and only
update its value to block or not s0i1.

Change-Id: I6516c60496974fd6d98421b794f4f6fb0718b1ce
Tracked-On: https://jira01.devtools.intel.com/browse/AW-6335


Signed-off-by: Simon Dubray <simonx.dubray@intel.com>
Reviewed-on: https://android.intel.com/597693


Reviewed-by: jenkins_ndg <jenkins_ndg@intel.com>
Reviewed-by: Korpershoek, MattijsX <mattijsx.korpershoek@intel.com>
Reviewed-by: Whitfield, MichaelX <michaelx.whitfield@intel.com>
Reviewed-by: Rouis, KhalifaX <khalifax.rouis@intel.com>
Reviewed-by: Jacquet, CyrilX <cyrilx.jacquet@intel.com>
Reviewed-by: Ledentec, AlexandreX <alexandrex.ledentec@intel.com>
Reviewed-by: Zaghdoud, WalidX <walidx.zaghdoud@intel.com>
Reviewed-by: Tasayco Loarte, VictorX <victorx.tasayco.loarte@intel.com>