ethtool: do not print warning for applications using legacy API

ethtool: do not print warning for applications using legacy API

In kernel log ths message appears on every boot:
 "warning: `NetworkChangeNo' uses legacy ethtool link settings API,
  link modes are only partially reported"

When ethtool link settings API changed, it started complaining about
usages of old API. Ironically, the original patch was from google but
the application using the legacy API is chrome.

Linux ABI is fixed as much as possible. The kernel must not break it
and should not complain about applications using legacy API's.
This patch just removes the warning since using legacy API's
in Linux is perfectly acceptable.

Fixes: 3f1ac7a700d0 ("net: ethtool: add new ETHTOOL_xLINKSETTINGS API")
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David Decotigny <decot@googlers.com>
Signed-off-by: David S. Miller <davem@davemloft.net>