msm: camera: isp: Move event bottom-halves to hardware layer

Currently the bottom half for all hardware events resides in
the hardware manager layer. This bottom half polls all VFE
hardware for the occurrence of all types of events every time
it is invoked. This change moves bottom-half processing to
the hardware layer and adds an event callback function in the
hardware manager layer. This callback function is invoked by
the bottom-halves in the hardware layer with knowledge of the
specific resource and event type and hardware index, thus
eliminating the need to poll all hardware for all types of
events.

Change-Id: If1a50e2386d6d0d73f9e8b9ecceed72fcb73023c
Signed-off-by: Venkat Chinta <vchinta@codeaurora.org>