CONFIG_S5P_PM is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_S5P_PM.
Result is shown for kernelversion 6.5.1

CONFIG_S5P_PM (not configurable)

modulename: pm.ko

and/or

s5p-pm.ko

configname: CONFIG_S5P_PM

Linux Kernel Configuration
└─>S5P_PM
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Common code for power management support on S5P and newer SoCs
Note: Do not select this for S5P6440 and S5P6450.

source code:
arch/arm/mach-exynos/pm.c