cpufreq: cpu0: don't validate clock on clk_put()

CPU clk is not optional for this driver and probe would fail if it couldn't find
a suitable clock.

And so, while calling clk_put() we don't need to validate clocks.

Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>