net/ethernet: tundra: fix dump_eth_one warning in tsi108_eth

The call site for this function appears as:

  #ifdef DEBUG
        data->msg_enable = DEBUG;
        dump_eth_one(dev);
  #endif

...leading to the following warning for !DEBUG builds:

drivers/net/ethernet/tundra/tsi108_eth.c:169:13: warning: 'dump_eth_one' defined but not used [-Wunused-function]
 static void dump_eth_one(struct net_device *dev)
             ^

...when using the arch/powerpc/configs/mpc7448_hpc2_defconfig

Put the function definition under the same #ifdef as the call site
to avoid the warning.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>