msm: sde: disable support for v4l2 event subscription

V4l2 event subscription is not used by rotator, and
default implementation on 4.9 is causing failure during
file release. Disable v4l2 event subscription for rotator
to avoid invalid file release.

Change-Id: I486f2eba7112852a1c818efeeb86033f17139b33
Signed-off-by: Alan Kwong <akwong@codeaurora.org>