ARM: dts: msm: Populate OPP table for GFX clock on MSM8937/SDM439

For GPU thermal mitigation, there is need to populate OPP
table for gfx3d clock source so add support for the same.

Change-Id: I72d33260c96ffe738ec8b0d5f25acbe818ac2e8c
Signed-off-by: Odelu Kukatla <okukatla@codeaurora.org>