CONFIG_DT_XLP_FVP is not available for thedefaultarchitecture x86.
Result is shown for architecture mips
default or selected kernelversion does not have config value CONFIG_DT_XLP_FVP.
Result is shown for kernelversion 6.9.5

Built-in device tree for XLP FVP boards

configname: CONFIG_DT_XLP_FVP

Linux Kernel Configuration
└─>Built-in device tree for XLP FVP boards
In linux kernel since version 3.12 (release Date: 2013-11-03)  
Add an FDT blob for XLP FVP board into the kernel.
This DTB will be used if the firmware does not pass in a DTB
pointer to the kernel. The corresponding DTS file is at
arch/mips/netlogic/dts/xlp_fvp.dts