default or selected kernelversion does not have config value CONFIG_MTD_BCM963XX.
Result is shown for kernelversion 6.2.5

Map driver for Broadcom BCM963xx boards

modulename: bcm963xx-flash.ko

configname: CONFIG_MTD_BCM963XX

Linux Kernel Configuration
└─>Device Drivers
└─>Memory Technology Device (MTD) support
└─>Mapping drivers for chip access
└─>Map driver for Broadcom BCM963xx boards
In linux kernel since version 2.6.37 (release Date: 2011-01-04)  
Support for parsing CFE image tag and creating MTD partitions on
Broadcom BCM63xx boards.

source code:
drivers/mtd/maps//bcm963xx-flash.c