Merge branch 'arc_emac'

Beniamino Galvani says:

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net: arc_emac: fix tx issues

the patches below solve some issues found in the tx ring reclaim
strategy currently implemented in the arc_emac driver.

Without these patches a simple outgoing UDP flow blocks almost
immediately with the socket send buffer full, until some new rx
packets trigger a clean of the tx ring.

Everything seems to work fine on a Radxa Rock with this fix applied.
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Signed-off-by: David S. Miller <davem@davemloft.net>