msm: camera: Add new sof event to include nanosecond timestamp

Thirdparty EIS need sof timestamp to be in nanoseconds and
this change will send new event sof_nanosec to get
nanosec timestamp.

Change-Id: Ia9884a2612cc3aa1153b4677521fce7ddfb8d1ba
Signed-off-by: Mounika Reddy Tangirala <mtangi@codeaurora.org>