dpaa_eth: use AVOIDBLOCK for Tx confirmation queues

The AVOIDBLOCK flag determines the Tx confirmation queues processing
to be redirected to any available CPU when the current one is slow
in processing them. This may result in a higher Tx confirmation
interrupt count but may reduce pressure on a certain CPU that with
the previous setting would process all Tx confirmation frames.

Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>