ARM: dts: msm: Add ADSPRPC mem region DT entry for sm6150

Add ADSPRPC mem region DT entry for remote heap use case for sm6150.

Change-Id: Iad08aa97cfa5c0d0fb9f2413b35934d9d99aafb3
Acked-by: Himateja Reddy <hmreddy@qti.qualcomm.com>
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>