etnaviv: fix non-pointsprite points on GC7000L

Fixes these deqp tests (and more):
dEQP-GLES2.functional.draw.draw_arrays.points.single_attribute
dEQP-GLES2.functional.draw.draw_arrays.points.multiple_attributes
dEQP-GLES2.functional.draw.draw_arrays.points.default_attribute
dEQP-GLES2.functional.draw.draw_elements.points.single_attribute
dEQP-GLES2.functional.draw.draw_elements.points.multiple_attributes
dEQP-GLES2.functional.draw.draw_elements.points.default_attribute

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>

src/gallium/drivers/etnaviv/etnaviv_shader.c

@@ -151,6 +151,10 @@ etna_link_shaders(struct etna_context *ctx, struct compiled_shader_state *cs,
       cs->VS_OUTPUT_COUNT_PSIZE = cs->VS_OUTPUT_COUNT;
    }
 
+   /* if fragment shader doesn't read pointcoord, disable it */
+   if (link.pcoord_varying_comp_ofs == -1)
+      cs->PA_CONFIG &= ~VIVS_PA_CONFIG_POINT_SPRITE_ENABLE;
+
    cs->VS_LOAD_BALANCING = vs->vs_load_balancing;
    cs->VS_START_PC = 0;