Revert "msm: camera: reqmgr: Adds total ordering of reqs for all pd devices"

This reverts commit ef0cd84c.
This revert will ensure that sensor and ISP will continue to apply as
long as there is no open request.

Change-Id: I7a261a3496484901038e696d753f5f627f673f6d
Signed-off-by: Venkat Chinta <vchinta@codeaurora.org>