Fixup gsp synch

Fixes issues with GSP synchronization. This is mostly experimental work that has been a result of trial and error, so I can't guarantee accuracy. However, I can assert the following:
* All known applications that worked (to my knowledge) still work
* Fixes the loading animation in Cubic Ninja
* Cave Story 3D runs 10X faster, and gets past the opening logos
* Other games (while not showing additional gfx) seem to no longer hang (e.g. Cubic Ninja, Cave Story 3D, Reto City Rampage)
This variable is being reset to zero every single time, so there's no use making it a static variable (and also, @bunnei, that probably means that this isn't doing what you're expecting it to do).