dpaa2-eth: transform dpaa2_eth_queue_count into a macro

Transform dpaa2_eth_queue_count into a macro to follow the
the convention used by dpaa2_eth_fs_count and other functions.

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