ARM: dts: msm: Set 1x DDR BW vote for MSM8920 GPU

Currently GPU is voting 2X DDR BW vote which is resulting
DDR to run at higher clock. Modify DDR BW vote 1x to keep
DDR clock at required level.

CRs-Fixed: 1094304
Change-Id: Ib5085e89bf16198a1fd0f555a9fd5dc9b0e486c1
Signed-off-by: Hareesh Gundu <hareeshg@codeaurora.org>