ethtool: allow ETHTOOL_GSSET_INFO for users

[ Upstream commit f80400a26a2e8bff541de12834a1134358bb6642 ]

Allow ETHTOOL_GSSET_INFO ethtool ioctl() for unprivileged users.
ETHTOOL_GSTRINGS is already allowed, but is unusable without this one.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>