arm64: dts: a3720: add support for espressobin with populated emmc

Import armada-3720-espressobin-emmc.dts from Linux, but use sdhc1 for
emmc, since our dtsi is still based on downstream and sdhc0 is used for
the sd card.

Signed-off-by: Andre Heider <a.heider@gmail.com>
diff --git a/doc/README.marvell b/doc/README.marvell
index 6fc5ac8..6f05ad4 100644
--- a/doc/README.marvell
+++ b/doc/README.marvell
@@ -43,8 +43,11 @@
         In order to prevent this, the required device-tree MUST be set during compilation.
         All device-tree files are located in ./arch/arm/dts/ folder.
 
-	For other DB boards (MacchiatoBin, EspressoBin and 3700 DB board) compile u-boot with
-	just default device-tree from defconfig using:
+	For the EspressoBin board with populated eMMC device use
+		# make DEVICE_TREE=armada-3720-espressobin-emmc
+
+	For other DB boards (MacchiatoBin, EspressoBin without soldered eMMC and 3700 DB board)
+	compile u-boot with just default device-tree from defconfig using:
 
 		# make