net/wan: dscc4: remove broken dscc4 driver

Using static analysis, I discovered that the "dpriv->pci_priv->pdev"
pointer is always NULL.  This pointer was supposed to be initialized
during probe and is essential for the driver to work.  It would be easy
to add a "ppriv->pdev = pdev;" to dscc4_found1() but this driver has
been broken since before we started using git and no one has complained
so probably we should just remove it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>