cpufreq: qoriq: rename the driver

This driver works on all QorIQ platforms which include
ARM-based cores and PPC-based cores.
Rename it in order to represent better.

Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>