cpufreq: drivers: don't check range of target freq in .target()

Cpufreq core checks the range of target_freq before calling driver->target() and
so we don't need to do it again.

Remove it.

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