CONFIG_CPU_FREQ_PMAC is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Support for Apple PowerBooks

modulename: cpufreq_32.ko

configname: CONFIG_CPU_FREQ_PMAC

Linux Kernel Configuration
└─>Platform support
└─>CPU Frequency drivers
└─>Support for Apple PowerBooks
In linux kernel since version 2.6.15 (release Date: 2006-01-02)  
This adds support for frequency switching on Apple PowerBooks,
this currently includes some models of iBook & Titanium
PowerBook.

source code:
arch/powerpc/platforms/powermac/cpufreq_32.c
selects
CONFIG_CPU_FREQ_TABLE

depends
CONFIG_ADB_PMU
CONFIG_CPU_FREQ
CONFIG_PPC32