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

CONFIG_FSL_CORENET_RCPM (not configurable)

modulename: fsl_rcpm.ko

configname: CONFIG_FSL_CORENET_RCPM

Linux Kernel Configuration
└─>FSL_CORENET_RCPM
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This option enables support for RCPM (Run Control/Power Management).

source code:
arch/powerpc/sysdev/fsl_rcpm.c
is depended by
CONFIG_FSL_SOC_BOOKE