CONFIG_MACH_MX31LILLY is not available for thedefaultarchitecture x86.
Result is shown for architecture arm
default or selected kernelversion does not have config value CONFIG_MACH_MX31LILLY.
Result is shown for kernelversion 6.9.9

Support MX31 LILLY-1131 platforms (INCO startec)

modulename: mach-mx31lilly.ko

configname: CONFIG_MACH_MX31LILLY

Linux Kernel Configuration
└─>Freescale i.MX family
└─>Support MX31 LILLY-1131 platforms (INCO startec)
In linux kernel since version 2.6.31 (release Date: 2009-09-09)  
Include support for mx31 based LILLY1131 modules. This includes
specific configurations for the board and its peripherals.

source code:
/arch/arm/mach-imx/