gpio: it87: add support for IT8772F Super I/O.

From the datasheet, the GPIO interface is identical to IT8728 (same
description), so just add it to the same case as the other chip.
Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.eu>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-it87.c

@@ -2,6 +2,7 @@
  *  GPIO interface for IT87xx Super I/O chips
  *
  *  Author: Diego Elio Pettenò <flameeyes@flameeyes.eu>
+ *  Copyright (c) 2017 Google, Inc.
  *
  *  Based on it87_wdt.c     by Oliver Schuster
  *           gpio-it8761e.c by Denis Turischev
@@ -39,6 +40,7 @@
 #define IT8728_ID	0x8728
 #define IT8732_ID	0x8732
 #define IT8761_ID	0x8761
+#define IT8772_ID	0x8772
 
 /* IO Ports */
 #define REG		0x2e
@@ -314,6 +316,7 @@ static int __init it87_gpio_init(void)
 		break;
 	case IT8728_ID:
 	case IT8732_ID:
+	case IT8772_ID:
 		gpio_ba_reg = 0x62;
 		it87_gpio->io_size = 8;
 		it87_gpio->output_base = 0xc8;