CONFIG_MPC85xx_MDS is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

Freescale MPC85xx MDS

modulename: mpc85xx_mds.ko

configname: CONFIG_MPC85xx_MDS

Linux Kernel Configuration
└─>Machine Type
└─>Freescale MPC85xx MDS
In linux kernel since version 2.6.21 (release Date: 2007-04-25)  
This option enables support for the MPC85xx MDS board

source code: