iio: accel: st_accel: add support to lng2dm

add support to STMicroelectronics LNG2DM accelerometer to
st_accel framework

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index c6cc2c0..c68bdb6 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -127,7 +127,8 @@
 	help
 	  Say yes here to build support for STMicroelectronics accelerometers:
 	  LSM303DLH, LSM303DLHC, LIS3DH, LSM330D, LSM330DL, LSM330DLC,
-	  LIS331DLH, LSM303DL, LSM303DLM, LSM330, LIS2DH12, H3LIS331DL.
+	  LIS331DLH, LSM303DL, LSM303DLM, LSM330, LIS2DH12, H3LIS331DL,
+	  LNG2DM
 
 	  This driver can also be built as a module. If so, these modules
 	  will be created: