ARM: dts: msm: update sleep vote node for sm8150

Display module keeps fix 400mbps sleep vote on mnoc,
ebi and llcc. This does not need split vote because
it is same for all three nodes. Create single node
for this vote to reduce the bus vote latency.

Change-Id: I850ab1fdcaa05db389c1a4a163af34db6865f545
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>