gpio: arizona: Remove unused header(s)

Some of the headers are unused in the driver, remove them.

While at it, sort headers alphabetically.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/gpio/gpio-arizona.c

@@ -7,13 +7,12 @@
  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  */
 
+#include <linux/gpio/driver.h>
 #include <linux/kernel.h>
-#include <linux/slab.h>
 #include <linux/module.h>
-#include <linux/gpio/driver.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
-#include <linux/seq_file.h>
+#include <linux/slab.h>
 
 #include <linux/mfd/arizona/core.h>
 #include <linux/mfd/arizona/pdata.h>