ARM: atmel: add sama5d4ek board support

The code for this board supports following features:
  - Boot media support: NAND flash/SD card/SPI flash
  - Support LCD display
  - Support ethernet
  - Support USB mass storage

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/configs/sama5d4ek_mmc_defconfig b/configs/sama5d4ek_mmc_defconfig
new file mode 100644
index 0000000..16a5ed7
--- /dev/null
+++ b/configs/sama5d4ek_mmc_defconfig
@@ -0,0 +1,3 @@
+CONFIG_SYS_EXTRA_OPTIONS="SAMA5D4,SYS_USE_MMC"
++S:CONFIG_ARM=y
++S:CONFIG_TARGET_SAMA5D4EK=y