msm: camera: Add input interface in SOF event

For Start of frame event send to userspace,
we need to know whether it is coming from the
pixel interface or the raw interface.
This change add the code to populate the
interface information.

Change-Id: Ie81473d9797e4514394fb89c39f576396e8ff478
Signed-off-by: Peter Liu <pingchie@codeaurora.org>