Merge branch 's390-qeth-fixes'

Julian Wiedmann says:

====================
s390/qeth: fixes 2018-04-19

Please apply the following qeth fixes for 4.17. The common theme
seems to be error handling improvements in various areas of cmd IO.

Patches 1-3 should also go back to stable.
====================

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