Merge branch 'macsec-key-length'

Antoine Tenart says:

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net: macsec: fix key length when offloading

The key length used to copy the key to offloading drivers and to store
it is wrong and was working by chance as it matched the default key
length. But using a different key length fails. Fix it by using instead
the max length accepted in uAPI to store the key and the actual key
length when copying it.

This was tested on the MSCC PHY driver but not on the Atlantic MAC
(looking at the code it looks ok, but testing would be appreciated).
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Signed-off-by: David S. Miller <davem@davemloft.net>