What kernel are you referring to? Is this the main kernel built by the linux source package? Or some custom kernel for your ARM builds?

What configuration entry would have to be enabled?

The wiki page you linked says that no upstream kernel have the corresponding USB ID yet. If that's the case, then there might be nothing to enable currently.

The kali kernel for amd64/x86 - if it were the arm kernels I'd just enable it; I do on most already.

I grabbed the WUSB6100M based on another user mentioning it, and the device ID does appear to be in the 4.18.10 kernel sources:

Bus 003 Device 003: ID 13b1:0042 Linksys
root@DESKTOP-ATSSHDA:~/source/linux-4.18.10# grep -ir 13b1 drivers/net/wireless/ath/ath10k
drivers/net/wireless/ath/ath10k/usb.c: {USB_DEVICE(0x13b1, 0x0042)}, / Linksys WUSB6100M /

CONFIG_ATH10K_USB is the configuration entry - it is marked as EXPERIMENTAL but I believe we already enable other experimental options.

I have requested this on the Debian side: https://bugs.debian.org/915083

Sophie is currently preparing a new kernel in kali-experimental and we just added that config option in our kernel build.

The fix was merged on the Debian side: https://salsa.debian.org/kernel-team/linux/commit/983a169e24d46fe0e398841df4417cf0d8653080

kernel is ready in kali-experimental
It will be in kali-dev later this day or tomorrow. I still have to test a few things.