CONFIG_MPC8540_ADS is not available for the selected architecture x86.
Result is shown for architecture powerpc

Freescale MPC8540 ADS

modulename: mpc85xx_ads.ko

configname: CONFIG_MPC8540_ADS

Linux Kernel Configuration
└─>Machine Type
└─>Freescale MPC8540 ADS
In linux kernel since version 2.6.12 )
This option enables support for the MPC 8540 ADS board
source code:
arch/powerpc/platforms/85xx/mpc85xx_ads.c

depends
CONFIG_MPC85xx or CONFIG_FSL_SOC_BOOKE |
| CONFIG_PPC32