ARM: dts: at91: add new compatibility string for macb on sama5d3

We need this new compatibility string as we experienced different behavior
for this 10/100Mbits/s macb interface on this particular SoC.
Backward compatibility is preserved as we keep the alternative strings.
Signed-off-by: NNicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/macb.txt

@@ -10,6 +10,7 @@ Required properties:
   Use "cdns,pc302-gem" for Picochip picoXcell pc302 and later devices based on
   the Cadence GEM, or the generic form: "cdns,gem".
   Use "atmel,sama5d2-gem" for the GEM IP (10/100) available on Atmel sama5d2 SoCs.
+  Use "atmel,sama5d3-macb" for the 10/100Mbit IP available on Atmel sama5d3 SoCs.
   Use "atmel,sama5d3-gem" for the Gigabit IP available on Atmel sama5d3 SoCs.
   Use "atmel,sama5d4-gem" for the GEM IP (10/100) available on Atmel sama5d4 SoCs.
   Use "cdns,zynq-gem" Xilinx Zynq-7xxx SoC.

arch/arm/boot/dts/sama5d3_emac.dtsi

@@ -41,7 +41,7 @@
 			};
 
 			macb1: ethernet@f802c000 {
-				compatible = "cdns,at91sam9260-macb", "cdns,macb";
+				compatible = "atmel,sama5d3-macb", "cdns,at91sam9260-macb", "cdns,macb";
 				reg = <0xf802c000 0x100>;
 				interrupts = <35 IRQ_TYPE_LEVEL_HIGH 3>;
 				pinctrl-names = "default";