bootcounter: add DM support for memory based bootcounter

add DM/DTS support for the memory based bootcounter
in drivers/bootcount/bootcount.c.

Let the old implementation in, so boards which have
not yet convert to DM/DTS do not break.

Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/doc/device-tree-bindings/misc/bootcounter.txt b/doc/device-tree-bindings/misc/bootcounter.txt
new file mode 100644
index 0000000..d32fbc3
--- /dev/null
+++ b/doc/device-tree-bindings/misc/bootcounter.txt
@@ -0,0 +1,21 @@
+U-Boot bootcounter Devicetree Binding
+=====================================
+
+The device tree node describes the U-Boot bootcounter
+memory based device binding.
+
+Required properties :
+
+- compatible : "u-boot,bootcount";
+- single-word : set this, if you have only one word space
+    for storing the bootcounter.
+
+Example
+-------
+
+MPC83xx based board:
+
+bootcount@0x13ff8 {
+	compatible = "u-boot,bootcount";
+	reg = <0x13ff8 0x08>;
+};