MUMBAI—Cyrus Mistry, the 54-year-old former chairman of Indian conglomerate Tata Sons, died in a road accident near financial capital Mumbai on Sunday, Indian police said. Mistry was ousted as chairman of Tata Sons, the holding company of the $300-billion salt-to-software Tata conglomerate, in a boardroom coup in 2016, sparking a long-drawn-out legal tussle on which…