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

Broadcom Broadband Carrier Access (BCA) origin SoC


Linux Kernel Configuration
└─>Platform selection
└─>Broadcom SoC Support
└─>Broadcom Broadband Carrier Access (BCA) origin SoC
In linux kernel since version 4.14.326 (release Date: 2023-09-23)  
Say Y if you intend to run the kernel on a Broadcom Broadband ARM-based
BCA chipset.

This enables support for Broadcom BCA ARM-based broadband chipsets,
including the DSL, PON and Wireless family of chips.