ARM: dts: msm: Fixed wrong MIN DCVS config for SDM845

Set GPU frequency to zero in case GPU goes to SLUMBER.

CRs-Fixed: 2062271
Change-Id: I7859a5e6e0e2aed5c10a0de26a89c356d9b434d9
Signed-off-by: George Shen <sqiao@codeaurora.org>