ravb_phy_start() may fail. If that happens, the TX queues will remain
started. Thus, move the netif_tx_start_all_queues() after PHY is
successfully initialized.

Fixes: c156633f ("Renesas Ethernet AVB driver proper")
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>