CPUFREQ: Loongson1: Use dev_get_platdata() to get platform_data

This patch uses dev_get_platdata() to get the platform_data
instead of referencing it directly.

Signed-off-by: Kelvin Cheung <keguang.zhang@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13054/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>