Make use of the new MMD accessors.

v2:
- fix SoB
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>