Add reboot reason on suspend/resume timeout.

This is needed to debug suspend/resume timeout issues. On reboot,
the bootloader will pick up this written reason and take actions.
For example, pass it along to Linux for tracking purpose.

Change-Id: I432a7bf17870f6c75372a8de9f83de237448e2ef
(cherry picked from commit f17d040a48b6c45f6fb624348cf276427724d04e)
2 files changed