MAINTAINERS: Add myself as maintainer of the scd4x driver

Signed-off-by: Roan van Dijk <roan@protonic.nl>
Link: https://lore.kernel.org/r/20211008101706.755942-3-roan@protonic.nlSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -16910,6 +16910,12 @@ F:	drivers/iio/chemical/scd30_core.c
 F:	drivers/iio/chemical/scd30_i2c.c
 F:	drivers/iio/chemical/scd30_serial.c
 
+SENSIRION SCD4X CARBON DIOXIDE SENSOR DRIVER
+M:	Roan van Dijk <roan@protonic.nl>
+S:	Maintained
+F:	Documentation/devicetree/bindings/iio/chemical/sensirion,scd4x.yaml
+F:	drivers/iio/chemical/scd4x.c
+
 SENSIRION SGP40 GAS SENSOR DRIVER
 M:	Andreas Klinger <ak@it-klinger.de>
 S:	Maintained