MAINTAINERS: fix broken ref for ABI sysfs-bus-counter-ftm-quaddec

There's a typo here:

	sysfs-bus-counter-ftm-quadddec -> sysfs-bus-counter-ftm-quaddec

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>