BofA analyst Julien Dumoulin-Smith upgraded SunPower Corp. to Neutral from Underperform with a price target of $23, up from $13 (3 percent downside). The re-rating followed the company’s analyst day, which he said offered clarity on the growth trajectory. Given what he calls “admittedly a robust turnaround plan with specific steps,” Dumoulin-Smith made “material” upward revisions to his estimates…