CONFIG_BOOTINFO_PROC is not available for thedefaultarchitecture x86.
Result is shown for architecture m68k

Export bootinfo in procfs

modulename: bootinfo_proc.ko

configname: CONFIG_BOOTINFO_PROC

Linux Kernel Configuration
└─>Export bootinfo in procfs
In linux kernel since version 3.14 (release Date: 2014-03-30)  
Say Y to export the bootinfo used to boot the kernel in a
"bootinfo" file in procfs. This is useful with kexec.

source code: