gpio: samsung: Use CONFIG_ARCH_S3C64XX to check for S3C64XX support

Since CONFIG_PLAT_S3C64XX is going to be removed, this patch modifies
the gpio-samsung driver to use the proper way of checking for S3C64xx
support - CONFIG_ARCH_S3C64XX.
Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

drivers/gpio/gpio-samsung.c

@@ -1033,7 +1033,7 @@ static int s3c24xx_gpiolib_fbank_to_irq(struct gpio_chip *chip, unsigned offset)
 }
 #endif
 
-#ifdef CONFIG_PLAT_S3C64XX
+#ifdef CONFIG_ARCH_S3C64XX
 static int s3c64xx_gpiolib_mbank_to_irq(struct gpio_chip *chip, unsigned pin)
 {
 	return pin < 5 ? IRQ_EINT(23) + pin : -ENXIO;
@@ -1174,7 +1174,7 @@ struct samsung_gpio_chip s3c24xx_gpios[] = {
  */
 
 static struct samsung_gpio_chip s3c64xx_gpios_4bit[] = {
-#ifdef CONFIG_PLAT_S3C64XX
+#ifdef CONFIG_ARCH_S3C64XX
 	{
 		.chip	= {
 			.base	= S3C64XX_GPA(0),
@@ -1227,7 +1227,7 @@ static struct samsung_gpio_chip s3c64xx_gpios_4bit[] = {
 };
 
 static struct samsung_gpio_chip s3c64xx_gpios_4bit2[] = {
-#ifdef CONFIG_PLAT_S3C64XX
+#ifdef CONFIG_ARCH_S3C64XX
 	{
 		.base	= S3C64XX_GPH_BASE + 0x4,
 		.chip	= {
@@ -1257,7 +1257,7 @@ static struct samsung_gpio_chip s3c64xx_gpios_4bit2[] = {
 };
 
 static struct samsung_gpio_chip s3c64xx_gpios_2bit[] = {
-#ifdef CONFIG_PLAT_S3C64XX
+#ifdef CONFIG_ARCH_S3C64XX
 	{
 		.base	= S3C64XX_GPF_BASE,
 		.config	= &samsung_gpio_cfgs[6],