3c980-TX needs EXTRA_PREAMBLE

The ethernet card 3c980-TX needs a mdio_sync() to initialize the ethernet
properly. This is forced by adding an EXTRA_PREAMBLE to its drv_flags.

Without this, the driver did not reconnect after a link loss.

Signed-off-by: Gunnar Larisch <Gunnar.Larisch@gmx.de>
Acked-by: Steffen Klassert <klassert@mathematik.tu-chemnitz.de>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>