Documentation/bindings: net: ocelot: document the PTP bank

One additional register range needs to be described within the Ocelot
device tree node: the PTP. This patch documents the binding needed to do
so.
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/mscc-ocelot.txt

@@ -12,6 +12,7 @@ Required properties:
   - "sys"
   - "rew"
   - "qs"
+  - "ptp" (optional due to backward compatibility)
   - "qsys"
   - "ana"
   - "portX" with X from 0 to the number of last port index available on that
@@ -44,6 +45,7 @@ Example:
 		reg = <0x1010000 0x10000>,
 		      <0x1030000 0x10000>,
 		      <0x1080000 0x100>,
+		      <0x10e0000 0x10000>,
 		      <0x11e0000 0x100>,
 		      <0x11f0000 0x100>,
 		      <0x1200000 0x100>,
@@ -57,9 +59,10 @@ Example:
 		      <0x1280000 0x100>,
 		      <0x1800000 0x80000>,
 		      <0x1880000 0x10000>;
-		reg-names = "sys", "rew", "qs", "port0", "port1", "port2",
-			    "port3", "port4", "port5", "port6", "port7",
-			    "port8", "port9", "port10", "qsys", "ana";
+		reg-names = "sys", "rew", "qs", "ptp", "port0", "port1",
+			    "port2", "port3", "port4", "port5", "port6",
+			    "port7", "port8", "port9", "port10", "qsys",
+			    "ana";
 		interrupts = <21 22>;
 		interrupt-names = "xtr", "inj";