r8169: Fix netpoll oops

Pass the correct thing to rtl8169_interrupt() from netpoll.

Cc: Realtek linux nic maintainers <nic_swsd@realtek.com>
Cc: netdev@vger.kernel.org
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Fixes: ebcd5daa ("r8169: change interrupt handler argument type")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>