default or selected kernelversion does not have config value CONFIG_BCM2835_VCHIQ_SUPPORT_MEMDUMP.
Result is shown for kernelversion 6.7-rc3

Support dumping memory contents to debug log

configname: CONFIG_BCM2835_VCHIQ_SUPPORT_MEMDUMP

Linux Kernel Configuration
└─>Device Drivers
└─>Staging drivers
└─>Broadcom VideoCore support
└─>Support dumping memory contents to debug log
In linux kernel since version 4.7.2 (release Date: 2016-08-20)  
BCM2835 VCHIQ supports the ability to dump the
contents of memory to the debug log. This
is typically only needed by diagnostic tools used
to debug issues with VideoCore.