msm:camera: add trace log support for VFE events

trace log support added for important VFE events,
these traces can be enabled with camera trace event.

Change-Id: I1e5c043ad3b69df632ff63130ff8eea10ab2097c
Signed-off-by: Srikanth Uyyala <suyyala@codeaurora.org>
Signed-off-by: Sumalatha Malothu <smalot@codeaurora.org>