CONFIG_CMDLINE_OVERWRITE is not available for thedefaultarchitecture x86.
Result is shown for architecture sh

Overwrite bootloader kernel arguments

configname: CONFIG_CMDLINE_OVERWRITE

Kernel command line
└─>Overwrite bootloader kernel arguments
In linux kernel since version 2.6.32 (release Date: 2009-12-02)  
Given string will overwrite any arguments passed in by
a bootloader.