iio: add Kconfig selects needed for triggered buffer compiles

Select IIO_BUFFER and IIO_TRIGGERED_BUFFER to compile.
Remove IIO_TRIGGER if present since IIO_BUFFER selects it.
Signed-off-by: Alison Schofield <amsfield22@gmail.com>
Cc: Daniel Baluta <daniel.baluta@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/Kconfig

@@ -20,6 +20,8 @@ config BMA180
 config BMA220
     tristate "Bosch BMA220 3-Axis Accelerometer Driver"
 	depends on SPI
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
     help
       Say yes here to add support for the Bosch BMA220 triaxial
       acceleration sensor.
@@ -234,7 +236,8 @@ config STK8312
 config STK8BA50
 	tristate "Sensortek STK8BA50 3-Axis Accelerometer Driver"
 	depends on I2C
-	depends on IIO_TRIGGER
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 	help
 	  Say yes here to get support for the Sensortek STK8BA50 3-axis
 	  accelerometer.

drivers/iio/humidity/Kconfig

@@ -6,6 +6,8 @@ menu "Humidity sensors"
 config AM2315
     tristate "Aosong AM2315 relative humidity and temperature sensor"
     depends on I2C
+    select IIO_BUFFER
+    select IIO_TRIGGERED_BUFFER
     help
       If you say yes here you get support for the Aosong AM2315
       relative humidity and ambient temperature sensor.

drivers/iio/light/Kconfig

@@ -238,6 +238,8 @@ config MAX44000
 	tristate "MAX44000 Ambient and Infrared Proximity Sensor"
 	depends on I2C
 	select REGMAP_I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
 	help
 	 Say Y here if you want to build support for Maxim Integrated's
 	 MAX44000 ambient and infrared proximity sensor device.