net: phy: marvell-88x2222: 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 <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/phy/marvell-88x2222.c

···
  */
 #include <linux/module.h>
 #include <linux/phy.h>
-#include <linux/gpio.h>
 #include <linux/delay.h>
 #include <linux/mdio.h>
 #include <linux/marvell_phy.h>
 #include <linux/of.h>
-#include <linux/of_gpio.h>
 #include <linux/sfp.h>
 #include <linux/netdevice.h>