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

PMC-Sierra MSP chipsets

configname: CONFIG_PMC_MSP

System type
└─>PMC-Sierra MSP chipsets
In linux kernel since version 2.6.23 (release Date: 2007-10-09)  
This adds support for the PMC-Sierra family of Multi-Service
Processor System-On-A-Chips. These parts include a number
of integrated peripherals, interfaces and DSPs in addition to
a variety of MIPS cores.