opp: Allow opp-supported-hw to contain multiple versions

The bindings allow multiple versions to be passed to "opp-supported-hw"
property, either of which can result in enabling of the OPP.

Update code to allow that.

Tested-by: Stephan Gerhold <stephan@gerhold.net>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>