PM / OPP: Update performance state when freq == old_freq

At boot up, CPUFreq core performs a sanity check to see if the system is
running at a frequency defined in the frequency table of the CPU. If so,
we try to find a valid frequency (lowest frequency greater than the
currently programmed frequency) from the table and set it. When the call
reaches dev_pm_opp_set_rate(), it calls _find_freq_ceil(opp_table,
&old_freq) to find the previously configured OPP and this call also
updates the old_freq. This eventually sets the old_freq == freq (new
target requested by cpufreq core) and we skip updating the performance
state in this case.

Fix this by also updating the performance state when the old_freq ==
freq.

Fixes: ca1b5d77

 ("OPP: Configure all required OPPs")
Cc: v5.0 <stable@vger.kernel.org> # v5.0
Reported-by: Niklas Cassel <niklas.cassel@linaro.org>
Tested-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>