MIPS: dts: mscc: describe the PTP ready interrupt

This patch adds a description of the PTP ready interrupt, which can be
triggered when a PTP timestamp is available on an hardware FIFO.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: davem@davemloft.net
Cc: richardcochran@gmail.com
Cc: alexandre.belloni@bootlin.com
Cc: UNGLinuxDriver@microchip.com
Cc: ralf@linux-mips.org
Cc: jhogan@kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: thomas.petazzoni@bootlin.com
Cc: allan.nielsen@microchip.com

arch/mips/boot/dts/mscc/ocelot.dtsi

@@ -139,8 +139,8 @@
 				    "port2", "port3", "port4", "port5", "port6",
 				    "port7", "port8", "port9", "port10", "qsys",
 				    "ana", "s2";
-			interrupts = <21 22>;
-			interrupt-names = "xtr", "inj";
+			interrupts = <18 21 22>;
+			interrupt-names = "ptp_rdy", "xtr", "inj";
 
 			ethernet-ports {
 				#address-cells = <1>;