power: reset: Add snapshot of msm-poweroff

Add snapshot of msm-poweroff driver as of commit <a0e0de0156d6> ("Merge
"diag: Donot open mhi channels on usb connect"").

Change-Id: I584b7d6187394610e084e955bf1503d5c68f560d
[eberman@codeaurora.org: migrate SCM calls, support driver as a module
with probe and restart handler]
Signed-off-by: Elliot Berman <eberman@codeaurora.org>