CONFIG_ARC_LPB_DISABLE is not available for thedefaultarchitecture x86.
Result is shown for architecture arc

Disable loop buffer (LPB)

configname: CONFIG_ARC_LPB_DISABLE

Linux Kernel Configuration
└─>ARC Architecture Configuration
└─>ARC CPU Configuration
└─>Disable loop buffer (LPB)
In linux kernel since version 5.1 (release Date: 2019-05-05)  
On HS cores, loop buffer (LPB) is programmable in runtime and can
be optionally disabled.