cpufreq: pmac32-cpufreq: Fix refcount leak bug
In the Linux kernel, the following vulnerability has been resolved:

cpufreq: pmac32-cpufreq: Fix refcount leak bug

In pmac_cpufreq_init_MacRISC3(), we need to add corresponding
of_node_put() for the three node pointers whose refcount have
been incremented by of_find_node_by_name().