ARM: dts: msm: Add reg dma offsets to sde node for sdm845

Sdm845 sde contains the reg dma hardware block. Change adds the offsets
for reg dma and dspp features that use reg dma block.

Change-Id: Id21fbf4cc5c700a3c36b658f4017201f65d989e5
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>