Fix some minor problems in comments of etherdevice.h
* Warning is out dated, file hasn't moved or disappeared in many years and
is unlikely to do so soon.
* Capitalize Ethernet consistently since it is a proper name
* Fix descriptive comment of padding
* Spelling and grammar fix for alignment comment
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>