ARM: dts: msm: Add virtual thermal zone definition for SDM845

Add virtual thermal zone definition for GPU and CPU cluster virtual
sensors for SDM845.

Configure GPU virtual sensor to throttle GPU cooling device when the
virtual sensor crosses 95C.

Change-Id: I7462464bc4079ce7731b23a9923de4ff206b18fa
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>