ARM: OMAP: Fix OMAP1 compilation after MPUIO check change

The recent MPUIO range change fix breaks compilation if
CONFIG_ARCH_OMAP24XX isn't defined; it should be OMAP_MAX_GPIO_LINES not
MAX_GPIO_LINES I believe. This one liner fixes it.
Signed-off-by: Jonathan McDowell <noodles@earth.li>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/gpio.c

@@ -216,7 +216,7 @@ static inline int gpio_valid(int gpio)
 		return -1;
 #ifndef CONFIG_ARCH_OMAP24XX
 	if (OMAP_GPIO_IS_MPUIO(gpio)) {
-		if (gpio >= MAX_GPIO_LINES + 16)
+		if (gpio >= OMAP_MAX_GPIO_LINES + 16)
 			return -1;
 		return 0;
 	}