drivers: gpio: amd-fch: make resource struct const

The struct resource field is statically initialized
and may never change. Therefore make it const.

Signed-off-by: Enrico Weigelt <info@metux.net>
Link: https://lore.kernel.org/r/1560787211-15443-1-git-send-email-info@metux.net
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-amd-fch.c

@@ -25,7 +25,7 @@
 #define AMD_FCH_GPIO_FLAG_WRITE		BIT(22)
 #define AMD_FCH_GPIO_FLAG_READ		BIT(16)
 
-static struct resource amd_fch_gpio_iores =
+static const struct resource amd_fch_gpio_iores =
 	DEFINE_RES_MEM_NAMED(
 		AMD_FCH_MMIO_BASE + AMD_FCH_GPIO_BANK0_BASE,
 		AMD_FCH_GPIO_SIZE,