etnaviv: fix non-pointsprite points on GC7000L

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>