ARM64: dts: sm8150: enable new GPU step introduced by CAF for sm855

CAF introduced 675mhz GPU step in commit https://source.codeaurora.org/quic/la/kernel/msm-4.14/commit/?h=LA.UM.7.1.r1-14100-sm8150.0&id=1e7f876f13576e4082a9a36da1e06fec1760b9c5



enable this step on our device

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>