net: ethtool: don't require CAP_NET_ADMIN for ETHTOOL_GLINKSETTINGS

The ETHTOOL_GLINKSETTINGS command is deprecating the ETHTOOL_GSET
command and likewise it shouldn't require the CAP_NET_ADMIN capability.

Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>