By Kane Wu and Julie Zhu HONG KONG (Reuters) - Global investment firms Carlyle Group and EQT, alongside regional players HongShan Capital Group and Boyu Capital, are preparing final offers for a controlling stake in Starbucks' China operations, said five people with knowledge of the matter. Starbucks has asked them to submit binding bids by early October, said three of the sources, who declined to be identified as the information was private. An agreement could be reached by the end of next month, one o ...