msm: cpufreq: Implement suspend/resume for cpufreq driver

Cpufreq suspend variable get's updated in kernel pm notifier
callback which gets called in process context. This will create
window where cpufreq governor may try to change the frequency
before suspend variable is updated while resume.

Define suspend/resume for cpufreq driver to update suspend variable
in atomic context.

Don't update the policy->cur upon cpufreq driver failure.

CRs-fixed: 423791
Change-Id: Id78705f5c3b8bf801c6253e9362299280903769f
Signed-off-by: Anji Jonnala <anjir@codeaurora.org>