net: introduce the MACSEC netdev feature

This patch introduce a new netdev feature, which will be used by drivers
to state they can perform MACsec transformations in hardware.

The patchset was gathered by Mark, macsec functinality itself
was implemented by Dmitry, Mark and Pavel Belous.

Change-Id: I84cc0abf852a5adb25d3f6d3fd100b1921b66165
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: Mark Starovoytov <mstarovoitov@marvell.com>
Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: 5908220b2b3d6918f88cd645a39e1dcb84d1c5d9
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


[quic_adamodar@quicinc.com: Moved upstream change in
 net/ethtool/common.c to net/core/ethtool.c]
Signed-off-by: Akshaya Damodaran <quic_adamodar@quicinc.com>