My PS told me it's a good idea to let my GP know that I'm having surgery. I'm sure there's good reasons for this!
Your GP will be able to see your medical record and might have reasons as to why surgery might not be a good idea. He/she might also send you for a blood workup to see whether your gyne is caused by a hormone imbalance, which is good to know as if this is the case there's nothing to say that your gyne won't resurface after surgery!
That said, you don't HAVE to tell your GP. If you're comfortable doing so, then go for it, as it's probably a good idea!