CONFIG_PM is not available for thedefaultarchitecture x86.
Result is shown for architecture m68knommu

Power Management support

modulename: pm.ko

and/or

sleep.ko

and/or

irq-pm.ko

and/or

pm-gpio.ko

and/or

mpc52xx_sleep.ko

and/or

lite5200_sleep.ko

and/or

sysfs.ko

and/or

main.ko

configname: CONFIG_PM

Linux Kernel Configuration
└─>Power management options
└─>Power Management support
In linux kernel since version 2.6.12  
Support processor power management modes