etnaviv: Fix point sprite rendering on GC3000

Setting PA_VIEWPORT_UNK state correctly is necessary to make point sprite
rendering on GC3000 work.
Signed-off-by: Wladimir J. van der Laan <laanwj@gmail.com>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

src/gallium/drivers/etnaviv/etnaviv_context.c

@@ -317,6 +317,8 @@ etna_cmd_stream_reset_notify(struct etna_cmd_stream *stream, void *priv)
    etna_set_state(stream, VIVS_GL_VERTEX_ELEMENT_CONFIG, 0x00000001);
    etna_set_state(stream, VIVS_RA_EARLY_DEPTH, 0x00000031);
    etna_set_state(stream, VIVS_PA_W_CLIP_LIMIT, 0x34000001);
+   etna_set_state(stream, VIVS_PA_VIEWPORT_UNK00A80, 0x38a01404);
+   etna_set_state(stream, VIVS_PA_VIEWPORT_UNK00A84, fui(8192.0));
 
    /* Enable SINGLE_BUFFER for resolve, if supported */
    etna_set_state(stream, VIVS_RS_SINGLE_BUFFER, COND(ctx->specs.single_buffer, VIVS_RS_SINGLE_BUFFER_ENABLE));