dt-bindings: power: Add Owl SPS power domains

Define power domains for all non-reserved S500 power gates.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NAndreas Färber <afaerber@suse.de>

Documentation/devicetree/bindings/power/actions,owl-sps.txt

+Actions Semi Owl Smart Power System (SPS)
+
+Required properties:
+- compatible          :  "actions,s500-sps" for S500
+- reg                 :  Offset and length of the register set for the device.
+- #power-domain-cells :  Must be 1.
+                         See macros in:
+                          include/dt-bindings/power/owl-s500-powergate.h for S500
+
+
+Example:
+
+		sps: power-controller@b01b0100 {
+			compatible = "actions,s500-sps";
+			reg = <0xb01b0100 0x100>;
+			#power-domain-cells = <1>;
+		};

include/dt-bindings/power/owl-s500-powergate.h

+/*
+ * Copyright (c) 2017 Andreas Färber
+ *
+ * SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+ */
+#ifndef DT_BINDINGS_POWER_OWL_S500_POWERGATE_H
+#define DT_BINDINGS_POWER_OWL_S500_POWERGATE_H
+
+#define S500_PD_VDE	0
+#define S500_PD_VCE_SI	1
+#define S500_PD_USB2_1	2
+#define S500_PD_CPU2	3
+#define S500_PD_CPU3	4
+#define S500_PD_DMA	5
+#define S500_PD_DS	6
+#define S500_PD_USB3	7
+#define S500_PD_USB2_0	8
+
+#endif