net: dpaa2-eth: rearrange variable in dpaa2_eth_get_ethtool_stats

Rearrange the variables in the dpaa2_eth_get_ethtool_stats() function so
that we adhere to the reverse Christmas tree rule.
Also, in the next patch we are adding more variables and I didn't know
where to place them with the current ordering.

Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>