CONFIG_PM is not available for thedefaultarchitecture x86.
Result is shown for architecture mips

Power Management support (EXPERIMENTAL)

modulename: pm.ko

and/or

standby.ko

and/or

main.ko

and/or

cpu.ko

and/or

suspend.ko

configname: CONFIG_PM

Linux/MIPS Kernel Configuration
└─>Executable file formats
└─>Power Management support (EXPERIMENTAL)
In linux kernel since version 2.6.12  
depends
CONFIG_EXPERIMENTAL
CONFIG_SOC_AU1X00