Merge branch 's390-net-updates'

Julian Wiedmann says:

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s390/iucv: updates 2021-06-11

please apply the following iucv patches to netdev's net-next tree.

This cleans up a pattern of forward declarations in two iucv drivers,
so that they stop causing compile warnings with gcc11.
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Signed-off-by: David S. Miller <davem@davemloft.net>