(Refiles to remove extraneous advisory) Jan 28 (Reuters) - Online trading platforms Robinhood and Interactive Brokers said on Thursday they had restricted trading in shares of GameStop, BlackBerry and other companies that have seen hefty gains this week due to a social media-driven trading frenzy. (Reporting by Sagarika Jaisinghani in Begaluru; Editing by Saumyadeb Chakrabarty)