cso_context: remove ability to restore VBs, const bufs, sampler views, images, perf++
This is meant to decrease CPU overhead and reduce the use of
cso_context when better solutions are possible.
These functions are removed. Gallium frontends should just use pipe_context:
Additionally, vertex buffers are passed through
cso_context but they are not saved there. The only remaining role of
cso_context with regard to vertex buffers is to decide whether to go through
u_vbuf or skip it.
u_vbuf also can't save and restore vertex buffers anymore.
This is how the states will be restored for meta ops:
- in st/mesa, set
st->dirty |= flagsto re-bind whatever state has been touched
- outside of st/mesa, there is new interface
st_context_iface::invalidate_statethat external modules can use to essentially set
st->dirtythrough it (like HUD)