misc: hi6421-spmi-pmic: Remove unused of_gpio.h

of_gpio.h is deprecated and subject to remove.
The driver doesn't use it, simply remove the unused header.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240304180737.1201566-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/hi6421v600-irq.c

@@ -11,7 +11,6 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/module.h>
-#include <linux/of_gpio.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/irqdomain.h>