lib8390: Remove unnecessary extern

Already declared in 8390.h
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/lib8390.c

@@ -108,7 +108,6 @@ int ei_debug = 1;
 /* Index to functions. */
 static void ei_tx_intr(struct net_device *dev);
 static void ei_tx_err(struct net_device *dev);
-void ei_tx_timeout(struct net_device *dev);
 static void ei_receive(struct net_device *dev);
 static void ei_rx_overrun(struct net_device *dev);