CONFIG_8xx_WDT is not available for the default architecture x86.
Result is shown for architecture um
default or selected kernelversion does not have config value CONFIG_8xx_WDT.
Result is shown for kernelversion

MPC8xx Watchdog Timer

modulename: mpc8xx_wdt.ko
configname: CONFIG_8xx_WDT

Linux Kernel Configuration
└─> Device Drivers
└─> Watchdog Timer Support
└─> MPC8xx Watchdog Timer

source code: