net: macsec: introduce the macsec_context structure

This patch introduces the macsec_context structure. It will be used
in the kernel to exchange information between the common MACsec
implementation (macsec.c) and the MACsec hardware offloading
implementations. This structure contains pointers to MACsec specific
structures which contain the actual MACsec configuration, and to the
underlying device (phydev for now).

Change-Id: Ib7d4e6f1667c2f4679e4d51d68671075462237db
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: 76564261a7db80c5f5c624e0122a28787f266bdf
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


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