Sunderland are set to earn themselves some cash after Southampton beat Leeds United in the Championship play-off final at the weekend. The two sides came up against each other at Wembley Stadium, a year after they were both relegated from the Premier League. After finishing three points behind the Whites, Adam Armstrong’s first-half goal proved to be the difference in the English capital and sent the Saints straight back to the top flight. One player who could now be playing Premier League football without really lifting a finger is Ross Stewart, who left Sunderland for the south-coast last su…