Documentation: devicetree: fix typo in MediaTek ethernet device-tree binding

fix typo in
Documentation/devicetree/bindings/net/mediatek-net.txt

Cc: devicetree@vger.kernel.org
Reported-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NSean Wang <sean.wang@mediatek.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/mediatek-net.txt

@@ -34,7 +34,7 @@ Required properties:
 - phy-handle: see ethernet.txt file in the same directory and
 	the phy-mode "trgmii" required being provided when reg
 	is equal to 0 and the MAC uses fixed-link to connect
-	with inernal switch such as MT7530.
+	with internal switch such as MT7530.
 
 Example: