arm64: dts: qcom: pmk8350: add reboot-mode node using sdam_2 nvmem

Introduce sdam_2 node, which is to be used via nvmem for power on
reasons during reboot. Add supported PoN reasons supported via sdam_2
node.
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230503-topic-sm8450-upstream-reboot-reason-v1-1-c5ac3dd5b49f@linaro.org

arch/arm64/boot/dts/qcom/pmk8350.dtsi

@@ -13,6 +13,16 @@
 	#define PMK8350_SID 0
 #endif
 
+/ {
+	reboot-mode {
+		compatible = "nvmem-reboot-mode";
+		nvmem-cells = <&reboot_reason>;
+		nvmem-cell-names = "reboot-mode";
+		mode-recovery = <0x01>;
+		mode-bootloader = <0x02>;
+	};
+};
+	
 &spmi_bus {
 	pmk8350: pmic@PMK8350_SID {
 		compatible = "qcom,pmk8350", "qcom,spmi-pmic";
@@ -66,6 +76,19 @@ pmk8350_rtc: rtc@6100 {
 			status = "disabled";
 		};
 
+		pmk8350_sdam_2: nvram@7100 {
+			compatible = "qcom,spmi-sdam";
+			reg = <0x7100>;
+			#address-cells = <1>;
+			#size-cells = <1>;
+			ranges = <0 0x7100 0x100>;
+
+			reboot_reason: reboot-reason@48 {
+				reg = <0x48 0x1>;
+				bits = <1 7>;
+			};
+		};
+
 		pmk8350_gpios: gpio@b000 {
 			compatible = "qcom,pmk8350-gpio", "qcom,spmi-gpio";
 			reg = <0xb000>;