iio: move 3-wire spi initialization to st_sensors_spi

Some devices need to be configured with special bit in order to
use spi 3-wire. This was done during device identification phase.
Instead, let's move this part as spi specific.
Doing this the check_device_support function becomes a simple
device id check, so let's rename it.

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

include/linux/iio/common/st_sensors.h

@@ -338,8 +338,7 @@ int st_sensors_get_settings_index(const char *name,
 				  const struct st_sensor_settings *list,
 				  const int list_length);
 
-int st_sensors_check_device_support(struct iio_dev *indio_dev,
-	int num_sensors_list, const struct st_sensor_settings *sensor_settings);
+int st_sensors_verify_id(struct iio_dev *indio_dev);
 
 ssize_t st_sensors_sysfs_sampling_frequency_avail(struct device *dev,
 				struct device_attribute *attr, char *buf);

include/linux/iio/common/st_sensors_spi.h

@@ -13,7 +13,7 @@
 #include <linux/spi/spi.h>
 #include <linux/iio/common/st_sensors.h>
 
-void st_sensors_spi_configure(struct iio_dev *indio_dev,
-			struct spi_device *spi, struct st_sensor_data *sdata);
+int st_sensors_spi_configure(struct iio_dev *indio_dev,
+			     struct spi_device *spi);
 
 #endif /* ST_SENSORS_SPI_H */