net: stmmac: fix dma operation mode config for older versions

The dma operation mode configuration routine was wrongly moved to a
function (stmmac_mtl_configuration) that is only executed if the
core version is >= 4.00.

Fixes: 6deee222 ("net: stmmac: prepare dma op mode config for multiple queues")
Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Reviewed-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>