msm: camera: core: Avoid concurrency between stop and pfdump

Camera context layer checks the state of the driver context and
allow the events to proceed. Two events should not execute
concurrently on context. Currently Dumping platform data
executing concurrently with flush or stop. This changes avoid
the concurrent execute of dump pf data and other events.

Change-Id: Iee674eb877c54cec3566abafeaf91c4e9a0cadcd
Signed-off-by: Ravikishore Pampana <rpampana@codeaurora.org>