power: reset: Add snapshot of vm power off driver

Add snapshot of vm power off driver as of msm-4.14
'commit 77a20e0a50e1
("power: reset: cache flush before VM restart")'.

Change-Id: I380b16f46429711284bb6717847a1eef5d8ee9b1
Signed-off-by: Ping Jiang <scottjiang@codeaurora.org>