CONFIG_MPC85xx_RDB is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc
Freescale P102x MBG/UTM/RDB
modulename: mpc85xx_rdb.ko
configname: CONFIG_MPC85xx_RDB
Linux Kernel Configuration
└─>Freescale Book-E Machine Type
└─>Freescale P102x MBG/UTM/RDB
In linux kernel since version 2.6.32 (release Date: 2009-12-02)
This option enables support for the P1020 MBG PC, P1020 UTM PC,
P1020 RDB PC, P1020 RDB PD, P1020 RDB, P1021 RDB PC, P1024 RDB,
and P1025 RDB boards
P1020 RDB PC, P1020 RDB PD, P1020 RDB, P1021 RDB PC, P1024 RDB,
and P1025 RDB boards