By Joshua Browne Manchester City are hoping to muscle in and snatch Argentine teenager Franco Mastantuono away from the clutches of Real Madrid, according to reports in Spain. The 16-year-old has been extensively linked with 15-time Champions League winners Madrid since the turn of the year, with an agreement over a future transfer already mooted by some local media outlets. Mastantuono has a £45m release clause in his River Plate contract – standard procedure these days for some of South America’s brightest young talents – but Madrid have not formally agreed to pay the figure to the Argentine…