intel: Remove GL_NV_point_sprite from extension list

i830 does not (and cannot!) support the any of the non-default
GL_POINT_SPRITE_R_MODE_NV settings.  i915 and i965 could, but
currently do not.  In both cases it would require mucking about with
the fragment shader.

src/mesa/drivers/dri/intel/intel_extensions.c

@@ -114,7 +114,6 @@ static const struct dri_extension card_extensions[] = {
    { "GL_MESA_pack_invert",               NULL },
    { "GL_MESA_ycbcr_texture",             NULL },
    { "GL_NV_blend_square",                NULL },
-   { "GL_NV_point_sprite",                GL_NV_point_sprite_functions },
    { "GL_NV_vertex_program",              GL_NV_vertex_program_functions },
    { "GL_NV_vertex_program1_1",           NULL },
    { "GL_SGIS_generate_mipmap",           NULL },