bindings: MAINTAINERS: fix references to Allwinner LRADC

The file got converted to yaml, but the reference at MAINTAINERS
was not updated.

Fixes: 5bf2845e ("dt-bindings: input: Convert Allwinner LRADC to a schema")
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

MAINTAINERS

@@ -15540,7 +15540,7 @@ SUN4I LOW RES ADC ATTACHED TABLET KEYS DRIVER
 M:	Hans de Goede <hdegoede@redhat.com>
 L:	linux-input@vger.kernel.org
 S:	Maintained
-F:	Documentation/devicetree/bindings/input/sun4i-lradc-keys.txt
+F:	Documentation/devicetree/bindings/input/allwinner,sun4i-a10-lradc-keys.yaml
 F:	drivers/input/keyboard/sun4i-lradc-keys.c
 
 SUNDANCE NETWORK DRIVER