Cambodia's Prince Norodom Sihanouk, in an abrupt about-face, said he is willing to continue peace talks with Cambodian Premier Hun Sen. Sihanouk announced last week that he was canceling a planned two rounds of talks in 1988 with Hun Sen. When they met for the first time earlier this month, the two men agreed to seek a political solution to the conflict pitting Hun Sen's Vietnamese-installed government against a coalition resistance movement. Sihanouk's latest statement said the second round of talks will be held near Paris, with the date to be set by Hun Sen. He said he changed his mind about canceling the talks in light of adverse reactions at this week's Assn. of Southeast Asian Nations summit in Manila.