st/mesa: Re-assign vs in locations after updating nir info for ffvp/ARB_vp

st/mesa: Re-assign vs in locations after updating nir info for ffvp/ARB_vp

After call to nir_shader_gather_info - inputs_read may have changed so
st_nir_assign_vs_in_locations should be called for shader to remain in
sync with vbo state.

Fixes piglit tests:
  gl-1.0-fpexceptions
  gl-1.1-color-material-unused-normal-array
  arb_vertex_program-unused-attributes
regression on several gallium drivers.

Fixes: d684fb37bfbc47d098158cb03c0672119a4469fe
Signed-off-by: Danylo Piliaiev <danylo.piliaiev@globallogic.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4645>