Add htu21 meas-spec driver support

Support for HTU21 temperature & humidity sensor

Signed-off-by: Ludovic Tancerel <ludovic.tancerel@maplehightech.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/humidity/Kconfig b/drivers/iio/humidity/Kconfig
index 353ee9a..a7e5ee5 100644
--- a/drivers/iio/humidity/Kconfig
+++ b/drivers/iio/humidity/Kconfig
@@ -22,6 +22,17 @@
 	 To compile this driver as a module, choose M here: the module
 	 will be called hdc100x.
 
+config HTU21
+	tristate "Measurement Specialties HTU21 humidity & temperature sensor"
+	depends on I2C
+        select IIO_MS_SENSORS_I2C
+	help
+	  If you say yes here you get support for the Measurement Specialties
+	  HTU21 humidity and temperature sensor.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called htu21.
+
 config SI7005
 	tristate "SI7005 relative humidity and temperature sensor"
 	depends on I2C