cpufreq: tegra186: add CPUFREQ_NEED_INITIAL_FREQ_CHECK flag
The driver doesn't provide ->get() method to read current frequency and
the frequency is set to 0 at initialization which makes the driver fail
at initialization time.
Set the CPUFREQ_NEED_INITIAL_FREQ_CHECK flag for the driver, so the
cpufreq core checks for the unlisted frequency and sets the CPU to a
valid frequency from the frequency table.