ARM: dts: msm: add cti save entry to cpu cti dt nodes for msmzirc

Add entry to CoreSight cpu CTI device tree nodes to enable saving
and restoring CTI registers on L2 SCU rail power down.

Change-Id: Ief0d139edb0fad77fb326d826ac1bb67d042dbe0
Signed-off-by: Sarangdhar Joshi <spjoshi@codeaurora.org>