ARM: at91: USB AT91 gadget registration for module

Registration of at91_udc as a module will enable SoC
related code.

Fix following an idea from Karel Znamenacek.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Karel Znamenacek <karel@ryston.cz>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: stable <stable@vger.kernel.org>
diff --git a/arch/arm/mach-at91/at91rm9200_devices.c b/arch/arm/mach-at91/at91rm9200_devices.c
index 18bacec..97676bd 100644
--- a/arch/arm/mach-at91/at91rm9200_devices.c
+++ b/arch/arm/mach-at91/at91rm9200_devices.c
@@ -83,7 +83,7 @@
  *  USB Device (Gadget)
  * -------------------------------------------------------------------- */
 
-#ifdef CONFIG_USB_AT91
+#if defined(CONFIG_USB_AT91) || defined(CONFIG_USB_AT91_MODULE)
 static struct at91_udc_data udc_data;
 
 static struct resource udc_resources[] = {