CONFIG_ARCH_BRCMSTB is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

Broadcom BCM7XXX based boards

modulename: brcmstb_dpfe.ko

configname: CONFIG_ARCH_BRCMSTB

Linux Kernel Configuration
└─>Broadcom SoC Support
└─>Broadcom BCM7XXX based boards
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Say Y if you intend to run the kernel on a Broadcom ARM-based STB
chipset.

This enables support for Broadcom ARM-based set-top box chipsets,
including the 7445 family of chips.

source code: