PM / devfreq: Add suspend and resume apis

Add devfreq suspend/resume apis for devfreq users. This patch
supports suspend and resume of devfreq load monitoring, required
for devices which can idle.

Signed-off-by: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --cc drivers/devfreq/devfreq.c
Simple merge

diff --cc drivers/devfreq/governor.h
Simple merge

diff --cc drivers/devfreq/governor_simpleondemand.c
Simple merge

diff --cc include/linux/devfreq.h
Simple merge