arm64: dts: apm: Add DT node for X-Gene v2 SLIMpro Mailbox I2C Driver

Add DT node to enable SLIMpro Mailbox I2C Driver for
X-Gene v2 platforms.

Signed-off-by: Duc Dang <dhdang@apm.com>

arch/arm64/boot/dts/apm/apm-shadowcat.dtsi

@@ -467,6 +467,11 @@
 					0x0 0x7 0x4>;
 		};
 
+		i2cslimpro {
+			compatible = "apm,xgene-slimpro-i2c";
+			mboxes = <&mailbox 0>;
+		};
+
 		serial0: serial@10600000 {
 			device_type = "serial";
 			compatible = "ns16550";