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>

MAINTAINERS

@@ -6327,7 +6327,7 @@ FLEXTIMER FTM-QUADDEC DRIVER
 M:	Patrick Havelange <patrick.havelange@essensium.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
-F:	Documentation/ABI/testing/sysfs-bus-counter-ftm-quadddec
+F:	Documentation/ABI/testing/sysfs-bus-counter-ftm-quaddec
 F:	Documentation/devicetree/bindings/counter/ftm-quaddec.txt
 F:	drivers/counter/ftm-quaddec.c