ARM: dts: msm: add nodes for etm save and restore for mdmfermium

Add device tree entries for ETM save-restore across power collapse
using memory mapped access.

Change-Id: Ib6a66b096bd92b703c09e6241cb6f83c12c015b5
Signed-off-by: Shaoqing Liu <shaoqingliu@codeaurora.org>