msm: sde: reduce kickoff timeout to 2 vsyncs

Current kickoff timeout is much longer than necessary.
Reduce it to 2 vsyncs of slowest frame rate at 24Hz so
it would signal much earlier than fence timeout.

CRs-Fixed: 2009714
Change-Id: I1c20889d009b97c4cb36faf7f7468f6388717c93
Signed-off-by: Alan Kwong <akwong@codeaurora.org>