CONFIG_ARCH_VULCAN is not available for thedefaultarchitecture x86.
Result is shown for architecture arm64

Broadcom Vulcan SOC Family

configname: CONFIG_ARCH_VULCAN

Linux Kernel Configuration
└─>Platform selection
└─>Broadcom Vulcan SOC Family
In linux kernel since version 4.1 (release Date: 2015-06-21)  
This enables support for Broadcom Vulcan SoC Family

selects
CONFIG_GPIOLIB

is selected by
CONFIG_GPIO_XLP