arm64: dts: qcom: msm8976: add compatible fallback to mailbox

MSM8976 mailbox is compatible with MSM8994.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230322174148.810938-5-krzysztof.kozlowski@linaro.org

arch/arm64/boot/dts/qcom/msm8976.dtsi

@@ -1035,7 +1035,8 @@ intc: interrupt-controller@b000000 {
 		};
 
 		apcs: mailbox@b011000 {
-			compatible = "qcom,msm8976-apcs-kpss-global", "syscon";
+			compatible = "qcom,msm8976-apcs-kpss-global",
+				     "qcom,msm8994-apcs-kpss-global", "syscon";
 			reg = <0x0b011000 0x1000>;
 			#mbox-cells = <1>;
 		};