Merge branch 'arcnet-fixes'

Michael Grzeschik says:

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arcnet: Collection of latest fixes

Here we sum up the recent fixes I collected on the way to use and
stabilise the framework. Part of it is an possible deadlock that we
prevent as well to fix the calculation of the dev_id that can be setup
by an rotary encoder. Beside that we added an trivial spelling patch and
fix some wrong and missing assignments that improves the code footprint.
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Signed-off-by: David S. Miller <davem@davemloft.net>