CONFIG_XIP_KERNEL is not available for thedefaultarchitecture x86.
Result is shown for architecture arm26

Execute In Place (XIP) kernel image

configname: CONFIG_XIP_KERNEL

Linux Kernel Configuration
└─>General setup
└─>Execute In Place (XIP) kernel image
In linux kernel since version 2.6.12  
Select this option to create a kernel that can be programed into
the OS ROMs.