arm: mvebu: add DB-88F6820-AMC board

This board is a plug in card for Marvell's switch system development
kits. Form-factor aside it is similar to the DB-88F6820-GP with the
following differences.
- TCLK is 200MHz
- SPI1 is used
- No SATA
- No MMC
- NAND flash

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Chris Packham <judge.packham@gmail.com>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 1d41d48..df57288 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -70,6 +70,7 @@
 	armada-375-db.dtb			\
 	armada-388-clearfog.dtb			\
 	armada-388-gp.dtb			\
+	armada-385-amc.dtb			\
 	armada-xp-gp.dtb			\
 	armada-xp-maxbcm.dtb			\
 	armada-xp-synology-ds414.dtb		\