Brooks Koepka returned to Aronimink Golf Club on Thursday with more on his mind than just his clubs. He won the PGA Championship here in 2023, finishing 9-under over four rounds on this same Donald Ross course, which now hosts the 108th edition. Three years later, he started with a 1-under 69. At first glance, that score seemed solid, but his explanation told a different story. “Every round just seems to be the worst I can shoot. Hopefully, we c…