ethernet/tulip: DE4x5 needs VIRT_TO_BUS

The automated ARM build tests have shown that the tulip de4x5 driver
uses the old-style virt_to_bus() interface on some architectures.

Alpha, Sparc and PowerPC did not hit this problem, because they
use a different code path, and most other architectures actually
do provide VIRT_TO_BUS.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Grundler <grundler@parisc-linux.org>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>