cpufreq: davinci: Reuse cpufreq_generic_frequency_table_verify()

policy->freq_table will always be valid for this platform, otherwise
driver's probe() would fail. And so this routine will *always* return
after calling cpufreq_frequency_table_verify().

This can be done using the generic callback provided by core, lets use
it instead.

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