Add simple-battery binding

zephyr/dts/bindings/power/simple-battery.yaml

@@ -0,0 +1,17 @@
+# Copyright (c) 2020, Tobias Schramm <t.schramm@t-sys.eu>
+# SPDX-License-Identifier: Apache-2.0
+
+description: |
+    Description for a battery
+
+compatible: "simple-battery"
+
+include: base.yaml
+
+properties:
+    soc-voltage-mv:
+      type: array
+      required: true
+      description: |
+        Array containing pairs of state-of-charge and associated
+        open circuit battery voltage in millivolts