MAINTAINERS: add include/dt-bindings/input to INPUT DRIVERS

Maintainers of the directory Documentation/devicetree/bindings/input
are also the maintainers of the corresponding directory
include/dt-bindings/input.

Add the file entry for include/dt-bindings/input to the appropriate
section in MAINTAINERS.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20220613115654.28117-1-lukas.bulwahn@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: bulwahn

MAINTAINERS

@@ -9798,6 +9798,7 @@ F:	Documentation/devicetree/bindings/input/
 F:	Documentation/devicetree/bindings/serio/
 F:	Documentation/input/
 F:	drivers/input/
+F:	include/dt-bindings/input/
 F:	include/linux/input.h
 F:	include/linux/input/
 F:	include/uapi/linux/input-event-codes.h