CONFIG_KERNEL_NOBP is not available for thedefaultarchitecture x86.
Result is shown for architecture s390

Enable modified branch prediction for the kernel by default

configname: CONFIG_KERNEL_NOBP

Linux Kernel Configuration
└─>Processor type and features
└─>Enable modified branch prediction for the kernel by default
In linux kernel since version 4.2 (release Date: 2015-08-30)  
If this option is selected the kernel will switch to a modified
branch prediction mode if the firmware interface is available.
The modified branch prediction mode improves the behaviour in
regard to speculative execution.

With the option enabled the kernel parameter "nobp=0" or "nospec"
can be used to run the kernel in the normal branch prediction mode.

With the option disabled the modified branch prediction mode is
enabled with the "nobp=1" kernel parameter.

If unsure, say N.