CONFIG_WATCHDOG_SUN4V is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT

Sun4v Watchdog support

modulename: sun4v_wdt.ko

configname: CONFIG_WATCHDOG_SUN4V

Linux Kernel Configuration
└─>Device Drivers
└─>Watchdog Timer Support
└─>Sun4v Watchdog support
In linux kernel since version 4.1 (release Date: 2015-06-21)  
Say Y here to support the hypervisor watchdog capability embedded
in the SPARC sun4v architecture.

To compile this driver as a module, choose M here. The module will
be called sun4v_wdt.

source code: