net: axienet: fix spelling mistake in comment "Exteneded" -> "extended"

There is a spelling mistake in a comment. Fix it.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Acked-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/xilinx/xilinx_axienet.h

@@ -186,7 +186,7 @@
 #define XAE_RAF_TXVSTRPMODE_MASK	0x00000180 /* Tx VLAN STRIP mode */
 #define XAE_RAF_RXVSTRPMODE_MASK	0x00000600 /* Rx VLAN STRIP mode */
 #define XAE_RAF_NEWFNCENBL_MASK		0x00000800 /* New function mode */
-/* Exteneded Multicast Filtering mode */
+/* Extended Multicast Filtering mode */
 #define XAE_RAF_EMULTIFLTRENBL_MASK	0x00001000
 #define XAE_RAF_STATSRST_MASK		0x00002000 /* Stats. Counter Reset */
 #define XAE_RAF_RXBADFRMEN_MASK		0x00004000 /* Recv Bad Frame Enable */