net: usb: use ndo_siocdevprivate

The pegasus and rtl8150 drivers use SIOCDEVPRIVATE ioctls
to access their MII registers, in place of the normal
commands. This is broken for all compat ioctls today.

Change to ndo_siocdevprivate to fix it.

Cc: Petko Manolov <petkan@nucleusys.com>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>