CONFIG_MPC837x_RDB is not available for the selected architecture x86.
Result is shown for architecture powerpc
Freescale MPC837x RDB/WLAN
modulename: mpc837x_rdb.ko
configname: CONFIG_MPC837x_RDB
Linux Kernel Configuration
└─>83xx-based boards
└─>Freescale MPC837x RDB/WLAN
In linux kernel since version 2.6.25 (release Date: 2008-04-16)
This option enables support for the MPC837x RDB and WLAN Boards.