net: macsec: introduce MACsec ops

This patch introduces MACsec ops for drivers to support offloading
MACsec operations.

Change-Id: I860013e7872f19f0611d07dfd9d69284076c45fd
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: 0830e20b62ad156f7df5ff5b9c4cea280ebe8fef
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Karthik Rudrapatna <quic_krudrapa@quicinc.com>