MAINTAINERS: add entry for hmc425a driver.

Add Beniamin Bia and Michael Hennerich as maintainers for HMC425A
attenuator.

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

MAINTAINERS

@@ -1081,6 +1081,15 @@ F:	drivers/iio/adc/ltc249*
 X:	drivers/iio/*/adjd*
 F:	drivers/staging/iio/*/ad*
 
+ANALOG DEVICES INC HMC425A DRIVER
+M:	Beniamin Bia <beniamin.bia@analog.com>
+M:	Michael Hennerich <michael.hennerich@analog.com>
+L:	linux-iio@vger.kernel.org
+S:	Supported
+W:	http://ez.analog.com/community/linux-device-drivers
+F:	Documentation/devicetree/bindings/iio/amplifiers/adi,hmc425a.yaml
+F:	drivers/iio/amplifiers/hmc425a.c
+
 ANALOGBITS PLL LIBRARIES
 M:	Paul Walmsley <paul.walmsley@sifive.com>
 S:	Supported