Revert "net: macsec: update SCI upon MAC address change."

commit f8294836f687917fa7caed1a39a08611fcdf5b97 from
git@git.assembla.com:cavium/WindRiver.linux.git

This reverts commit 6fc498bc.

Commit 6fc498bc states:

    SCI should be updated, because it contains MAC in its first 6
    octets.

That's not entirely correct. The SCI can be based on the MAC address,
but doesn't have to be. We can also use any 64-bit number as the
SCI. When the SCI based on the MAC address, it uses a 16-bit "port
number" provided by userspace, which commit 6fc498bc overwrites
with 1.

In addition, changing the SCI after macsec has been setup can just
confuse the receiver. If we configure the RXSC on the peer based on
the original SCI, we should keep the same SCI on TX.

When the macsec device is being managed by a userspace key negotiation
daemon such as wpa_supplicant, commit 6fc498bc would also
overwrite the SCI defined by userspace.

Change-Id: Ifa44e8c7b97ef7f27dfc5256e5e05b853e3de287
Fixes: 6fc498bc ("net: macsec: update SCI upon MAC address change.")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://lore.kernel.org/r/9b1a9d28327e7eb54550a92eebda45d25e54dd0d.1660667033.git.sd@queasysnail.net


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Reviewed-on: https://sj1git1.cavium.com/c/IP/SW/kernel/linux/+/92181


Reviewed-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Tested-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Wenlin Kang <wenlin.kang@windriver.com>