CONFIG_MPC830x_RDB is not available for thedefaultarchitecture x86.
Result is shown for architecture powerpc
Freescale MPC830x RDB
modulename: mpc830x_rdb.ko
configname: CONFIG_MPC830x_RDB
Linux Kernel Configuration
└─>83xx-based boards
└─>Freescale MPC830x RDB
In linux kernel since version 2.6.36 (release Date: 2010-10-20)
This option enables support for the MPC8308 RDB board.