anv: remove incorrect polygonMode=point early-out

anv: remove incorrect polygonMode=point early-out

This is incorrect, because polygonMode only applies if the final
primitive type is a polygon; polygonMode doesn't apply to
line-primitives as the comment suggests.

The Vulkan 1.1 spec, section 26.11, "Polygons" defines that polygons are
separate from points and line segments:

" A polygon results from the decomposition of a triangle strip, triangle
  fan or a series of independent triangles. Like points and line segments,
  polygon rasterization is controlled by several variables in the
  VkPipelineRasterizationStateCreateInfo structure. "

Further, section 26.11.2, "Polygon Mode", only define polygonMode to
apply to polygons:

" Possible values of the VkPipelineRasterizationStateCreateInfo::polygonMode
  property of the currently active pipeline, specifying the method of
  rasterization for polygons, are: "

This seems to clearly define that polygonMode doesn't apply to points
and lines, so let's make sure that we don't early out with the wrong
value.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>