DM9000: Cleanups after the resource changes

Remove the now extraneous checks in dm9000_release_board()
now that the two-resource case is removed. Also remove the
check on pdev->num_resources, as we check the return data
from platform_get_resource() to ensure we have not only
the right number but the right type of resources as well.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>