net_device_manager: Fix invalid (and always true) comparison.
net_device_manager: Fix invalid (and always true) comparison.

Not tested, but seems to be in line of what was intended.

Signed-off-by: Moritz Hoffmann <53ba0aa052d551db5cb133c62d34e71044d0deba@inf.ethz.ch>

BarrelfishOS/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,kishoredbn/barrelfish,BarrelfishOS/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,kishoredbn/barrelfish,BarrelfishOS/barrelfish,BarrelfishOS/barrelfish,kishoredbn/barrelfish,BarrelfishOS/barrelfish,BarrelfishOS/barrelfish