exynos: Add proid_is_exynos542x() for common 542x

Add a convenience function for any Exynos 542x chip.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/mach-exynos/include/mach/gpio.h b/arch/arm/mach-exynos/include/mach/gpio.h
index 272e00b..f9975d7 100644
--- a/arch/arm/mach-exynos/include/mach/gpio.h
+++ b/arch/arm/mach-exynos/include/mach/gpio.h
@@ -1397,7 +1397,7 @@
 static inline struct gpio_info *get_gpio_data(void)
 {
 	if (cpu_is_exynos5()) {
-		if (proid_is_exynos5420() || proid_is_exynos5422())
+		if (proid_is_exynos542x())
 			return exynos5420_gpio_data;
 		else
 			return exynos5_gpio_data;
@@ -1414,7 +1414,7 @@
 static inline unsigned int get_bank_num(void)
 {
 	if (cpu_is_exynos5()) {
-		if (proid_is_exynos5420() || proid_is_exynos5422())
+		if (proid_is_exynos542x())
 			return EXYNOS5420_GPIO_NUM_PARTS;
 		else
 			return EXYNOS5_GPIO_NUM_PARTS;