msm: camera: flash: Moving flash off operation in stop dev ioctl

Currently flash off can happen as a part of flush all request.
Flush all can be trigger in between single session, and it is not
intend to flash off operation if torch is in on. This change moves
flash off operation in the stop device request, which seperates
flash off and flush all operation.

Change-Id: Iefb9468e2ce4b0bbd8974eec357be88bfacd3d40
Signed-off-by: Jigarkumar Zala <jzala@codeaurora.org>