default or selected kernelversion does not have config value CONFIG_MTD_PMC_MSP_RAMROOT.
Result is shown for kernelversion 5.3.7

Embedded RAM block device for root on PMC-Sierra MSP

modulename: pmcmsp-ramroot.ko

configname: CONFIG_MTD_PMC_MSP_RAMROOT

Linux Kernel Configuration
└─>Device Drivers
└─>Memory Technology Device (MTD) support
└─>Mapping drivers for chip access
└─>Embedded RAM block device for root on PMC-Sierra MSP
In linux kernel since version 2.6.24 (release Date: 2008-01-24)  
This provides support for the embedded root file system
on PMC MSP devices. This memory is mapped as a MTD block device.

source code: