iio: adc: spear_adc: align headers with IWYU principle

Remove unused includes and add what is being used:

#include <linux/array_size.h> // for ARRAY_SIZE
#include <linux/bits.h>  // for GENMASKxx
#include <linux/dev_printk.h> // for dev_err_probe, dev_info
#include <linux/math.h>  // for DIV_ROUND_UP
#include <linux/mutex.h> // for struct mutex
#include <linux/types.h> // for uXX definitions
#include <linux/iio/types.h> // for IIO_CHAN_INFO_*

Signed-off-by: Rodrigo Gobbi <rodrigo.gobbi.7@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Author: losgobbi

drivers/iio/adc/spear_adc.c

@@ -5,22 +5,25 @@
  * Copyright 2012 Stefan Roese <sr@denx.de>
  */
 
+#include <linux/array_size.h>
 #include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/completion.h>
-#include <linux/device.h>
+#include <linux/dev_printk.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
-#include <linux/kernel.h>
+#include <linux/math.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
-#include <linux/slab.h>
+#include <linux/types.h>
 
 #include <linux/iio/iio.h>
-#include <linux/iio/sysfs.h>
+#include <linux/iio/types.h>
 
 /* SPEAR registers definitions */
 #define SPEAR600_ADC_SCAN_RATE_LO(x)	((x) & 0xFFFF)