iio: adc: stm32-dfsdm: include stm32-dfsdm-adc.h

Fix the following sparse warnings:
  CHECK   drivers/iio/adc/stm32-dfsdm-adc.c
symbol 'stm32_dfsdm_get_buff_cb' was not declared. Should it be static?
symbol 'stm32_dfsdm_release_buff_cb' was not declared. Should it be static?

BTW, move interrupt.h to sort headers alphabetically.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/stm32-dfsdm-adc.c

@@ -8,11 +8,11 @@
 
 #include <linux/dmaengine.h>
 #include <linux/dma-mapping.h>
-#include <linux/interrupt.h>
+#include <linux/iio/adc/stm32-dfsdm-adc.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/hw-consumer.h>
-#include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>

include/linux/iio/adc/stm32-dfsdm-adc.h

@@ -9,6 +9,8 @@
 #ifndef STM32_DFSDM_ADC_H
 #define STM32_DFSDM_ADC_H
 
+#include <linux/iio/iio.h>
+
 int stm32_dfsdm_get_buff_cb(struct iio_dev *iio_dev,
 			    int (*cb)(const void *data, size_t size,
 				      void *private),