net/macb: bindings doc: Merge cdns-emac to macb

Merge two bindings for the same driver to together.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/net/cdns-emac.txt

-* Cadence EMAC Ethernet controller
-
-Required properties:
-- compatible: Should be "cdns,[<chip>-]{emac}"
-  Use "cdns,at91rm9200-emac" Atmel at91rm9200 SoC.
-  Use "cdns,zynq-gem" Xilinx Zynq-7xxx SoC.
-  Or the generic form: "cdns,emac".
-- reg: Address and length of the register set for the device
-- interrupts: Should contain macb interrupt
-- phy-mode: see ethernet.txt file in the same directory.
-
-Examples:
-
-	macb0: ethernet@fffc4000 {
-		compatible = "cdns,at91rm9200-emac";
-		reg = <0xfffc4000 0x4000>;
-		interrupts = <21>;
-		phy-mode = "rmii";
-		local-mac-address = [3a 0e 03 04 05 06];
-	};

Documentation/devicetree/bindings/net/macb.txt

@@ -2,6 +2,7 @@
 
 Required properties:
 - compatible: Should be "cdns,[<chip>-]{macb|gem}"
+  Use "cdns,at91rm9200-emac" Atmel at91rm9200 SoC.
   Use "cdns,at91sam9260-macb" for Atmel at91sam9 SoCs or the 10/100Mbit IP
   available on sama5d3 SoCs.
   Use "cdns,at32ap7000-macb" for other 10/100 usage or use the generic form: "cdns,macb".
@@ -10,7 +11,9 @@ Required properties:
   Use "atmel,sama5d2-gem" for the GEM IP (10/100) available on Atmel sama5d2 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.
   Use "cdns,zynqmp-gem" for Zynq Ultrascale+ MPSoC.
+  Or the generic form: "cdns,emac".
 - reg: Address and length of the register set for the device
 - interrupts: Should contain macb interrupt
 - phy-mode: See ethernet.txt file in the same directory.