FROMLIST: PM / devfreq: Restart previous governor if new governor fails to start

If the new governor fails to start, switch back to old governor so that the
devfreq state is not left in some weird limbo.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Bug: 155527102
Link: https://lore.kernel.org/lkml/1477360800-11509-1-git-send-email-skannan@codeaurora.org/


Signed-off-by: Saravana Kannan <saravanak@google.com>
Change-Id: If853c7d03b6ce6767047f17d747f62d850a7b3b4