msm: camera: initialize qos_request object

qos_request object is used between two drivers (msm, camera)
there can be a scenario qos_request being updated before
initialize.
fix: make sure initialize is called before update.

Change-Id: I5e7e1639577f30b671598663d3dd2f8e7f5c3f36
Signed-off-by: Mounika Reddy Tangirala <mtangi@codeaurora.org>