i915: Enable intel_render path for points

i915: Enable intel_render path for points

The sub-pixel adjustment for points was killed off in
 commit 60d762aa625095a8c1f9597d8530bb5a6fa61b4c
 Author: Xiang, Haihao <haihao.xiang@intel.com>
 Date:   Wed Jan 2 11:38:51 2008 +0800

    i915: Needn't adjust pixel centers. fix #12944

so if we don't need it in intel_tris.c we don't need it in
intel_render.c either, which means we can allow
intel_render.c to render points.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>