PM / OPP don't match for existing OPPs when list is empty

OPP list is guaranteed to be empty when 'dev_opp' is created. And so we don't
need to run the comparison loop with existing OPPs.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Change-Id: I0e6ace1a0b4e6ec73ba3640d9da0828c4bc984b0
Git-commit: a7470db6fec481b14afea117846fce383671ba59
Git-repo: https://github.com/torvalds/linux.git


Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>