msm: camera: reqmgr: Handle flash properly

Apply the flash at EOF and apply the other devices
at the EPOCH of next frame, then the flash can
cover all the exposure zone of current request.
Add the inject delay for SOF and EOF separate, then
we can use inject delay for more flexible frame
skip control.

CRs-Fixed: 2820683
Change-Id: Ic6a58327a0ae44c54190884ba42ea7926ec7c90e
Signed-off-by: Depeng Shao <depengs@codeaurora.org>