msm: camera: isp: Enable early EOF

This change enables generating EOF strobe immediately after
last line of the image. This feature reuses the START_LINE and
END_LINE fields of the VCROP register to know what the actual
frame height is. Hence this bit is enabled only when user
correctly programs the start and end lines of the vcrop register.
Also the change adds a debugfs to disable this feature.

Change-Id: I3b884a18ea50931cad58ee7d03829bfb596e01a2
Signed-off-by: Karthik Anantha Ram <kartanan@codeaurora.org>