HONG KONG, June 7 (Reuters) - Hong Kong shares could start higher on Thursday, tracking the overnight gains on Wall Street on signs that European policymakers could decide on a solution for ailing Spanish bank and the U.S. may take action to boost its economy. Chinese banks could see some support after China said it will delay bringing in tougher capital requirements for its banks until January to avoid squeezing credit conditions and further dragging already slackening economic growth.