Merge branch 'dsa-docs'

Vladimir Oltean says:

====================
Update DSA documentation

These are some updates of dsa.rst, since it hasn't kept up with
development (in some cases, even since 2017). I've added Fixes: tags as
I thought was appropriate.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Author: davem330