msm: camera: Add stream based event subscribe

ISP send V4L2 events to userspace for processing,
buffer divert events are stream based and image statistics
events on based on statistics type.
Add support to allow events subscription based on
stream index or statistics type.

Change-Id: I2a3399754b746acf105612a048e1b6a121f652b2
Signed-off-by: Kevin Chan <ktchan@codeaurora.org>
3 files changed