ARM: mx5: introduce SOC_IMX51

Introduce SOC_IMX51 to keep consistency with the other i.MX devices

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/plat-mxc/devices/platform-fec.c b/arch/arm/plat-mxc/devices/platform-fec.c
index 8d78aed..269ec78 100644
--- a/arch/arm/plat-mxc/devices/platform-fec.c
+++ b/arch/arm/plat-mxc/devices/platform-fec.c
@@ -31,7 +31,7 @@
 	imx_fec_data_entry_single(MX35);
 #endif
 
-#ifdef CONFIG_ARCH_MX51
+#ifdef CONFIG_SOC_IMX51
 const struct imx_fec_data imx51_fec_data __initconst =
 	imx_fec_data_entry_single(MX51);
 #endif