Link the net_device structure of the wireless part to the
corresponding device structure.

Without this, the sysfs node for this net_device would not have
'device' link.
Signed-off-by: NMasakazu Mokuno <mokuno@sm.sony.co.jp>
Acked-by: NDan Williams <dcbw@redhat.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>