ARM: dts: msm: configure vref LDO for isens hardware in SDM845

LMH DCVSh hardware will enable the vref LDO for the isens hardware.
Configure the vref LDO phandle for LMH DCVSh driver to enable in SDM845.

Change-Id: I0f393d54e32db38e4c6a9a3d5c3c7c5a16c27b1d
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>