msm: camera: Add support for multiple SOF events.

Multiple SOF events are required when running multiple HW streams on a
single VFE, and the user space needs to distinguish between different
SOFs in the different streams. Such situation can occur, when we have
one or more RDI streams in parallel with a PIX stream.

Change-Id: I1a1c5a21fb098fa76071799d183bbe6e4558b51c
Signed-off-by: Vladislav Hristov <vhrist@codeaurora.org>