mx51evk: Fix MX51EVK_USB_CLK_EN_B definition

As per the mx51evk schematics MX51EVK_USB_CLK_EN_B is GPIO2_1, not GPIO2_2.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
diff --git a/board/freescale/mx51evk/mx51evk.c b/board/freescale/mx51evk/mx51evk.c
index f1e5eb4..c7c21f3 100644
--- a/board/freescale/mx51evk/mx51evk.c
+++ b/board/freescale/mx51evk/mx51evk.c
@@ -112,7 +112,7 @@
 #ifdef CONFIG_USB_EHCI_MX5
 #define MX51EVK_USBH1_HUB_RST	IMX_GPIO_NR(1, 7)
 #define MX51EVK_USBH1_STP	IMX_GPIO_NR(1, 27)
-#define MX51EVK_USB_CLK_EN_B	IMX_GPIO_NR(2, 2)
+#define MX51EVK_USB_CLK_EN_B	IMX_GPIO_NR(2, 1)
 #define MX51EVK_USB_PHY_RESET	IMX_GPIO_NR(2, 5)
 
 static void setup_usb_h1(void)