arm64: dts: hikey960: Add optee node

This patch adds op-tee node for hikey960
Signed-off-by: NVictor Chong <victor.chong@linaro.org>
Signed-off-by: NWei Xu <xuwei5@hisilicon.com>

arch/arm64/boot/dts/hisilicon/hi3660-hikey960.dts

@@ -159,6 +159,13 @@
 		startup-delay-us = <70000>;
 		enable-active-high;
 	};
+
+	firmware {
+		optee {
+			compatible = "linaro,optee-tz";
+			method = "smc";
+		};
+	};
 };
 
 &i2c0 {