dts/arm/st: Provide basis for stm32wb device tree

Base .dtsi files for stm32wb series and stm32wb55 SoC.

Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>

dts/arm/st/wb/stm32wb.dtsi

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2019 Linaro Limited
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <arm/armv7-m.dtsi>
+
+/ {
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			device_type = "cpu";
+			compatible = "arm,cortex-m4f";
+			reg = <0>;
+		};
+	};
+
+	sram0: memory@20000000 {
+		device_type = "memory";
+		compatible = "mmio-sram";
+	};
+
+	soc {
+		flash-controller@58004000 {
+			compatible = "st,stm32wb-flash-controller";
+			label = "FLASH_CTRL";
+			reg = <0x58004000 0x400>;
+			interrupts = <4 0>;
+
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			flash0: flash@8000000 {
+				compatible = "soc-nv-flash";
+				label = "FLASH_STM32";
+			};
+		};
+	};
+};
+
+&nvic {
+	arm,num-irq-priority-bits = <4>;
+};

dts/arm/st/wb/stm32wb55.dtsi

@@ -0,0 +1,7 @@
+/*
+ * Copyright (c) 2018 Linaro Limited
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <st/wb/stm32wb.dtsi>