dt-bindings: net: micrel-ksz90x1.txt: Update for lan8841

The lan8841 has the same bindings as ksz9131, so just reuse the entire
section of ksz9131.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/micrel-ksz90x1.txt

@@ -158,6 +158,7 @@ KSZ9031:
         no link will be established.
 
 KSZ9131:
+LAN8841:
 
   All skew control options are specified in picoseconds. The increment
   step is 100ps. Unlike KSZ9031, the values represent picoseccond delays.