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

Freescale MPC8568 MDS / MPC8569 MDS / P1021 MDS

modulename: mpc85xx_mds.ko

configname: CONFIG_MPC85xx_MDS

Linux Kernel Configuration
└─>Freescale Book-E Machine Type
└─>Freescale MPC8568 MDS / MPC8569 MDS / P1021 MDS
In linux kernel since version 2.6.21 (release Date: 2007-04-25)  
This option enables support for the MPC8568 MDS, MPC8569 MDS and P1021 MDS boards

source code: