[PATCH v6 2/6] iio: dac: ad5504: Align headers with IWYU principle

Update the header inclusions to follow the IWYU principle and ensure
they are sorted alphabetically:

- Remove <linux/fs.h>, <linux/slab.h>, and <linux/kernel.h> as they
  are unused. The driver relies on devm_ managed allocations, so slab
  is not required.
- Replace <linux/bitops.h> with <linux/bits.h> as only the BIT() and
  GENMASK() macros are used.
- Add <linux/errno.h> and <linux/types.h> for error codes and data types.
- Add <asm/byteorder.h> for cpu_to_be16().
- Add <linux/array_size.h> for ARRAY_SIZE().
- Add <linux/kstrtox.h> for string to integer conversions.
- Replaced <linux/device.h> with <linux/dev_printk.h>

Signed-off-by: Taha Ed-Dafili <[email protected]>
---
 drivers/iio/dac/ad5504.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/dac/ad5504.c b/drivers/iio/dac/ad5504.c
index ad1a74678cf2..5c9c66b04154 100644
--- a/drivers/iio/dac/ad5504.c
+++ b/drivers/iio/dac/ad5504.c
@@ -5,22 +5,25 @@
  * Copyright 2011 Analog Devices Inc.
  */
 
-#include <linux/bitops.h>
-#include <linux/device.h>
-#include <linux/fs.h>
+#include <linux/array_size.h>
+#include <linux/bits.h>
+#include <linux/dev_printk.h>
+#include <linux/errno.h>
 #include <linux/interrupt.h>
-#include <linux/kernel.h>
+#include <linux/kstrtox.h>
 #include <linux/module.h>
 #include <linux/regulator/consumer.h>
-#include <linux/slab.h>
 #include <linux/spi/spi.h>
 #include <linux/sysfs.h>
+#include <linux/types.h>
 
 #include <linux/iio/dac/ad5504.h>
 #include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 
+#include <asm/byteorder.h>
+
 #define AD5504_RES_MASK			GENMASK(11, 0)
 #define AD5504_CMD_READ			BIT(15)
 #define AD5504_CMD_WRITE		0
-- 
2.55.0