CONFIG_PARSE_BOOTPARAM is not available for thedefaultarchitecture x86.
Result is shown for architecture xtensa

Parse bootparam block

configname: CONFIG_PARSE_BOOTPARAM

Linux Kernel Configuration
└─>Platform options
└─>Parse bootparam block
In linux kernel since version 4.2 (release Date: 2015-08-30)  
Parse parameters passed to the kernel from the bootloader. It may
be disabled if the kernel is known to run without the bootloader.

If unsure, say Y.