CONFIG_MPC85xx is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc

CONFIG_MPC85xx (not configurable)

configname: CONFIG_MPC85xx

Linux Kernel Configuration
└─>Platform support
└─>MPC85xx
In linux kernel since version 2.6.21 (release Date: 2007-04-25)  

depends
CONFIG_PPC_85xx