[PATCH] etnaviv: Fix point sprite issue on HALTI0

[Wladimir]

> I think it would be reasonable to re-emit the shader state (or maybe
> just the varyings) when the primitive type changes from points to
> non-points. It virtually never happens that the same shader combo is
> used for points and non-points.

Thinking about it, this might even simplify some contorted code we
currently have in the emit sequence with regard to pointsize VS
outputs. Which becomes even worse in GC7000 where there's more (USC /
buffering related) state depending on the exact number of VS outputs.

Hmm that state depends on point_size_per_vertex, not whether we're
rendering points. So I guess we'd want to re-link the shader if:

- switching from point to non-point rendering, or vice versa
- if rendering points AND point_size_per_vertex changes

Though as for the latter I have no clue where vivantes get the point
size from if !point_size_per_vertex, currently we don't handle
pipe_rasterizer_state->point_size at all, we pretty much just assume
point_size_per_vertex.

Wladimir