iio: Add new driver dht11

This driver handles DHT11 and DHT22 sensors.

Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index bcf7e9e..b3b5096 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -18,6 +18,7 @@
 obj-y += dac/
 obj-y += gyro/
 obj-y += frequency/
+obj-y += humidity/
 obj-y += imu/
 obj-y += light/
 obj-y += magnetometer/