conf: fix typos
ethernet: replace sysfs/enabled by 'ip link down'

Disabeling the ethernet pci device via "echo 0" to sysfs attr "enabled"
does not necessarily power down the device but rather decrements the
enabled counter. Even if the counter reaches 0 the device may still
drain power.
Shutting down the ethernet device via 'ip link set dev DEV down',
however, reduces power consumptions to 0 mW as indicated by powertop.
Merge pull request #30 from shuber2/ethernet-poweroff

Ethernet poweroff