msm: camera: reqmgr: Create workq based on driver requirement

Currently all workqueues are created as high priority and unbounded,
this change allows the driver to set the necessary flags while
creating workq.

Change-Id: I8bcc4c29419f19c326ca34a6927af9a04480ae40
Signed-off-by: Karthik Anantha Ram <kartanan@codeaurora.org>