The OPP table was freed, but not the individual OPPs which is done from
_dev_pm_opp_remove_table(). Fix it by calling _dev_pm_opp_remove_table()
as well.

Cc: 4.18 <stable@vger.kernel.org> # v4.18
Fixes: 3ba98324 ("PM / OPP: Get performance state using genpd helper")
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>