When the lower device's carrier is off, the macvlan devices's
carrier state should be checked to decide whether it needs to
be turned off. Currently the lower device's state is checked
a second time.

This still works, but unnecessarily tries to turn off the
carrier when its already off.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>