ARM: mx3/mx31_3ds: fix compiler warning without CONFIG_USB_ULPI

This fixes:

	arch/arm/mach-mx3/mach-mx31_3ds.c:249: warning: 'mx31_3ds_host2_init' defined but not used

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-mx3/mach-mx31_3ds.c b/arch/arm/mach-mx3/mach-mx31_3ds.c
index 2f41430..dacafcc 100644
--- a/arch/arm/mach-mx3/mach-mx31_3ds.c
+++ b/arch/arm/mach-mx3/mach-mx31_3ds.c
@@ -245,7 +245,7 @@
 	return err;
 }
 
-static int mx31_3ds_host2_init(struct platform_device *pdev)
+static int __maybe_unused mx31_3ds_host2_init(struct platform_device *pdev)
 {
 	int err;