ARM: dts: msm: Update DCVS table for sdm670 gpu

Increasing DDR freq is costly because CX rail has higher leakage
current. So instead of increasing DDR freq, increasing the GPU power
level gives similar performance at a lower overall power since there
is separate GX rail for GPU which has lower leakage current. This can
be achieved by keeping a lower ib vote for some of the GPU powerlevels.

Change-Id: I02f624919e9f57f742a2c7d70c3d36199e49b752
Signed-off-by: Akhil P Oommen <akhilpo@codeaurora.org>