default or selected kernelversion does not have config value CONFIG_AHCI_BRCMSTB.
Result is shown for kernelversion 5.4.33

Broadcom STB AHCI SATA support

modulename: ahci_brcmstb.ko


Linux Kernel Configuration
└─>Device Drivers
└─>Serial ATA and Parallel ATA drivers (libata)
└─>Broadcom STB AHCI SATA support
In linux kernel since version 4.2 (release Date: 2015-08-30)  
This option enables support for the AHCI SATA3 controller found on
STB SoC's.

If unsure, say N.

source code: