Other so-called "meme stocks," including GameStop Corp GME.N and U.S.-listed shares of Blackberry Ltd BB.N were also sharply higher, up 7% to 15%. {nL3N2NP2QW] Cruise operator Royal Caribbean RCL.N announced that six of its ships would begin sailing from Florida and Texas ports in July and August. By Stephen Culp NEW YORK, June 7 (Reuters) - Wall Street started the week mixed on Monday as buyers stood on the sidelines on news of a global minimum corporate tax rate and lingering inflation fears, and a lack of market-moving catalysts.