cpufreq: schedutil: Set dynamic_switching to true

Set dynamic_switching to 'true' to disallow use of schedutil governor
for platforms with transition_latency set to CPUFREQ_ETERNAL, as they
may not want to do automatic dynamic frequency switching.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>