arm: atmel: add gmac support for sama5d3xek board

add gmac support for sama5d3xek board, the gmac embedded in:
  - sama5d33, sama5d34, sama5d35

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/include/configs/sama5d3xek.h b/include/configs/sama5d3xek.h
index 10697d6..3dcf012 100644
--- a/include/configs/sama5d3xek.h
+++ b/include/configs/sama5d3xek.h
@@ -136,6 +136,11 @@
 #define CONFIG_NET_MULTI
 #define CONFIG_NET_RETRY_COUNT		20
 #define CONFIG_MACB_SEARCH_PHY
+#define CONFIG_RGMII
+#define CONFIG_CMD_MII
+#define CONFIG_PHYLIB
+#define CONFIG_PHY_MICREL
+#define CONFIG_PHY_MICREL_KSZ9021
 
 /* MMC */
 #define CONFIG_CMD_MMC