ARM: at91/usbh: fix overcurrent gpio setup

Use gpio_is_valid also for overcurrent pins (which are currently
negative in many board files).

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
diff --git a/arch/arm/mach-at91/at91sam9260_devices.c b/arch/arm/mach-at91/at91sam9260_devices.c
index aa1e587..414bd85 100644
--- a/arch/arm/mach-at91/at91sam9260_devices.c
+++ b/arch/arm/mach-at91/at91sam9260_devices.c
@@ -72,7 +72,7 @@
 
 	/* Enable overcurrent notification */
 	for (i = 0; i < data->ports; i++) {
-		if (data->overcurrent_pin[i])
+		if (gpio_is_valid(data->overcurrent_pin[i]))
 			at91_set_gpio_input(data->overcurrent_pin[i], 1);
 	}