Merge pull request #3119 from unknownbrackets/gpu-thread

Sync the GPU thread on list/draw sync
Avoid a possible thread sync issue.

Could be that it's about to wake listsync, does, and then we wait.
Oops, left these here.
Don't wait directly from GPUCommon, do it in sceGe.

Makes debugging a bit easier.
SyncThread before deciding if the fbo is dirty.

Fixes fps drops in yet other games with multithreading enabled.