r300: OQ rework

r300: OQ rework

Move to common code base so radeon/r200 can add support for this.
Make OQ start a state emitted like all normal state, and make no-tcl
flushing work in proper places.

Really need a generic post emit space reservation mechanism like max_state
so we can reserve some space for the emit

this code passes demos/arbocclude, piglit occlusion query and
glean occlusion query with TCL and NO-TCL on my rv530.